Apportionment and Redistricting Process for the U.S. House of Representatives

Changes from May 12, 2021 to November 22, 2021

This page shows textual changes in the document between the two versions indicated in the dates above. Textual matter removed in the later version is indicated with ~~red strikethrough~~ and textual matter added in the later version is indicated with blue.

Apportionment and Redistricting Process for
~~May 12~~November 22, 2021 , 2021
the U.S. House of Representatives
Sarah J. Eckman
The census, apportionment, and redistricting are interrelated activities that affect representation The census, apportionment, and redistricting are interrelated activities that affect representation
Analyst in American Analyst in American
in the U.S. House of Representatives. Congressional apportionment (or reapportionment) is the in the U.S. House of Representatives. Congressional apportionment (or reapportionment) is the
National Government National Government
process of dividing seats for the House among the 50 states following the decennial census. process of dividing seats for the House among the 50 states following the decennial census.

Redistricting refers to the process that follows, in which states create new congressional districts Redistricting refers to the process that follows, in which states create new congressional districts
or redraw existing district boundaries to adjust for population changes and/or changes in the or redraw existing district boundaries to adjust for population changes and/or changes in the

number of House seats for the state. At times, Congress has passed or considered legislation number of House seats for the state. At times, Congress has passed or considered legislation
addressing apportionment and redistricting processes under its broad authority to make law affecting House addressing apportionment and redistricting processes under its broad authority to make law affecting House ~~electio ns~~elections under under
Article I, Section 4, of the U.S. Constitution. These processes are all rooted in provisions in Article I, Section 2 (as Article I, Section 4, of the U.S. Constitution. These processes are all rooted in provisions in Article I, Section 2 (as ~~amen ded~~amended
by Section 2 of the Fourteenth Amendment). by Section 2 of the Fourteenth Amendment).
Seats for the House of Representatives are constitutionally required to be divided among the states, based on the population Seats for the House of Representatives are constitutionally required to be divided among the states, based on the population
size of each state. To determine how many Representatives each state is entitled to, the Constitution requires the national size of each state. To determine how many Representatives each state is entitled to, the Constitution requires the national
population to be counted every 10 years, which is done through the census. The population to be counted every 10 years, which is done through the census. The ~~Con stitution~~Constitution also limits the number of also limits the number of
Representatives to no more than one for every 30,000 persons, provided that each state receives at least one Representative. Representatives to no more than one for every 30,000 persons, provided that each state receives at least one Representative.
Additional parameters for the census and for apportionment have been established through federal statutes, including Additional parameters for the census and for apportionment have been established through federal statutes, including
timelines for these processes; the number of seats in the House; and the method by which House seats are divided among timelines for these processes; the number of seats in the House; and the method by which House seats are divided among
states. Congress began creating more permanent legislation by the early 20th century to provide recurring procedures for the states. Congress began creating more permanent legislation by the early 20th century to provide recurring procedures for the
census and apportionment, rather than passing measures each decade to address an upcoming reapportionment cycle. Federal census and apportionment, rather than passing measures each decade to address an upcoming reapportionment cycle. Federal
law related to the census process is found in Title 13 of the law related to the census process is found in Title 13 of the U.S. Code, and two key statutes affecting apportionment today are , and two key statutes affecting apportionment today are
the Permanent Apportionment Act of 1929 and the Apportionment Act of 1941. the Permanent Apportionment Act of 1929 and the Apportionment Act of 1941.
April 1 of a year ending in “0” marks the decennial census date and the start of the apportionment population counting April 1 of a year ending in “0” marks the decennial census date and the start of the apportionment population counting
process; the Secretary of Commerce is to report the apportionment population of each state to the President by the end of that process; the Secretary of Commerce is to report the apportionment population of each state to the President by the end of that
year. Within the first week of the first regular session of the next Congress, the President is to transmit a statement to the year. Within the first week of the first regular session of the next Congress, the President is to transmit a statement to the
House relaying state population information and the number House relaying state population information and the number ~~o f~~of Representatives each state is entitled to. For a discussion of Representatives each state is entitled to. For a discussion of
recent changes to this timeline, see CRS Insight IN11360, recent changes to this timeline, see CRS Insight IN11360, Apportionment and Redistricting Following the 2020 Census. Each . Each
state receives one Representative, as constitutionally required, and the remaining seats are distributed using a mathematical state receives one Representative, as constitutionally required, and the remaining seats are distributed using a mathematical
approach known as the method of equal proportions, established by the Apportionment Act of 1941. Essentially, a ranked approach known as the method of equal proportions, established by the Apportionment Act of 1941. Essentially, a ranked
“priority list” is created indicating which states receive the 51st-435th House seats, based on a calculation involving each “priority list” is created indicating which states receive the 51st-435th House seats, based on a calculation involving each
state’s population size and the number of additional seats a state has received. The U.S. apportionment population from the state’s population size and the number of additional seats a state has received. The U.S. apportionment population from the
2020 census was 331,108,434, reflecting a 7.1% increase since 2010, and 7 House seats were reapportioned among 13 states.2020 census was 331,108,434, reflecting a 7.1% increase since 2010, and 7 House seats were reapportioned among 13 states.
After a census and apportionment are completed, state officials receive updated population information from the U.S. Census After a census and apportionment are completed, state officials receive updated population information from the U.S. Census
Bureau and the state’s allocation of House seats from the Clerk of the House. Single-member House districts are required by Bureau and the state’s allocation of House seats from the Clerk of the House. Single-member House districts are required by
2 U.S.C. §2c, and certain other redistricting standards, largely related to the composition of districts, have been established by 2 U.S.C. §2c, and certain other redistricting standards, largely related to the composition of districts, have been established by
federal statute and various legal decisions. Current federal parameters related to redistricting criteria generally address federal statute and various legal decisions. Current federal parameters related to redistricting criteria generally address
population equality and protections against discrimination for racial and language minority groups under the Voting Rights population equality and protections against discrimination for racial and language minority groups under the Voting Rights
Act of 1965 (VRA), as amended. Previous federal apportionment statutes have, at times, included other district criteria, such Act of 1965 (VRA), as amended. Previous federal apportionment statutes have, at times, included other district criteria, such
as geographic compactness or contiguity, and these standards have sometimes been referred to in U.S. Supreme Court cases, as geographic compactness or contiguity, and these standards have sometimes been referred to in U.S. Supreme Court cases,
but they are not included in the current federal statutes that address the apportionment process. These redistricting principles but they are not included in the current federal statutes that address the apportionment process. These redistricting principles
and others, such as considering existing political boundaries, preserving communities of interest, and promoting political and others, such as considering existing political boundaries, preserving communities of interest, and promoting political
competition, have been commonly used across states, and many are reflected in state laws today. competition, have been commonly used across states, and many are reflected in state laws today.
The procedural elements of redistricting are generally governed by state laws, and state redistricting practices can vary The procedural elements of redistricting are generally governed by state laws, and state redistricting practices can vary
regarding the methods used for drawing districts, timeline for redistricting, and which actors (e.g., elected officials, regarding the methods used for drawing districts, timeline for redistricting, and which actors (e.g., elected officials,
designated redistricting commissioners, and/or members of the public) are involved in the process. Mapmakers must often designated redistricting commissioners, and/or members of the public) are involved in the process. Mapmakers must often
make trade-offs between one redistricting consideration and others, and making these trade-offs can add an additional make trade-offs between one redistricting consideration and others, and making these trade-offs can add an additional
challenge to an already complicated task of ensuring “fair” representation for district residents. Despite technological challenge to an already complicated task of ensuring “fair” representation for district residents. Despite technological
advances that make it easier to design districts with increasing geographic and demographic precision, the overall task of advances that make it easier to design districts with increasing geographic and demographic precision, the overall task of
redistricting remains complex and, in many instances, can be controversial. A majority of states, for example, faced legal redistricting remains complex and, in many instances, can be controversial. A majority of states, for example, faced legal
challenges to congressional district maps drawn following the 2010 census, and these legal challenges can take multiple years challenges to congressional district maps drawn following the 2010 census, and these legal challenges can take multiple years
to resolve. to resolve.
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Contacts
Author Information ........................................................................................................................ 26 25

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Apportionment and Redistricting Process for the U.S. House of Representatives

Introduction
Every 10 years, the U.S. population is counted through the national census, and districts for the Every 10 years, the U.S. population is counted through the national census, and districts for the
U.S. House of Representatives are readjusted to reflect the new population level and its U.S. House of Representatives are readjusted to reflect the new population level and its
distribution across states through the federal apportionment and state redistricting processes. The distribution across states through the federal apportionment and state redistricting processes. The
requirement to have proportional representation in the House is found in the U.S. Constitution, requirement to have proportional representation in the House is found in the U.S. Constitution,
and constitutional provisions also underlie other elements of the census, apportionment, and and constitutional provisions also underlie other elements of the census, apportionment, and
redistricting practicesredistricting practices.. Figure 1 provides a generalized timeline provides a generalized timeline for how these three interrelated for how these three interrelated
processes occur, and the sections of the report that follow provide additional information on processes occur, and the sections of the report that follow provide additional information on
apportionment and redistricting. For a discussion of how the Coronavirus Disease 2019 (COVID-apportionment and redistricting. For a discussion of how the Coronavirus Disease 2019 (COVID-
19) pandemic affected the timing of the most recent census and apportionment, see CRS Insight 19) pandemic affected the timing of the most recent census and apportionment, see CRS Insight
IN11360, IN11360, Apportionment and Redistricting Following the 2020 Census. For additional . For additional
information on the census process, see CRS Report R44788, information on the census process, see CRS Report R44788, The Decennial Census: Issues for
2020, and CRS In Focus IF11015, , and CRS In Focus IF11015, The 2020 Decennial Census: Overview and Issues..
Figure 1. Typical Timeline of Census, Apportionment, and Redistricting Process

Source: CRS compilation, CRS compilation, based on information from the U.S. Constitution,based on information from the U.S. Constitution, U.S. Code, U.S. Census Bureau, and , U.S. Census Bureau, and
state laws. Graphic created by Amberstate laws. Graphic created by Amber Hope Wilhelm,Hope Wilhelm, CRS Visual Information Specialist. CRS Visual Information Specialist.
Apportionment Process
Apportionment (or reapportionment) refers to the process of dividing seats in the U.S. House of Apportionment (or reapportionment) refers to the process of dividing seats in the U.S. House of
Representatives among the states. Article 1, Section 2, of the U.S. Constitution, as amended by Representatives among the states. Article 1, Section 2, of the U.S. Constitution, as amended by
Section 2 of the Fourteenth Amendment, requires that seats for Representatives are divided Section 2 of the Fourteenth Amendment, requires that seats for Representatives are divided
among states, based on the population size of each state. House seats today are among states, based on the population size of each state. House seats today are ~~real ocated~~reallocated due to due to
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changes in state populations, since the number of U.S. states (50) has remained constant since changes in state populations, since the number of U.S. states (50) has remained constant since
1959; in earlier eras, the addition of new states would also affect the reapportionment process, as 1959; in earlier eras, the addition of new states would also affect the reapportionment process, as
each state is each state is ~~constitutional y~~constitutionally required to receive at least one House seat. required to receive at least one House seat.
The 2020 census reported a 7.1% The 2020 census reported a 7.1% ~~overal~~ overall increase in the U.S. apportionment population since the increase in the U.S. apportionment population since the
2010 census, to 331,108,434 individuals.1 The ideal (or average) district population size increased 2010 census, to 331,108,434 individuals.1 The ideal (or average) district population size increased
across most states across most states ~~fol owing~~following the 2020 census, and some states experienced larger growth levels the 2020 census, and some states experienced larger growth levels
than others.2 Three states experienced decreases in average district population size following the than others.2 Three states experienced decreases in average district population size following the
2020 census.3 The average congressional district population for the United States following the 2020 census.3 The average congressional district population for the United States following the
2020 census was 761,169 individuals.4 Seven U.S. House seats shifted across states following the 2020 census was 761,169 individuals.4 Seven U.S. House seats shifted across states following the
2020 census; seven states lost seats and six states gained seats, distributed as shown 2020 census; seven states lost seats and six states gained seats, distributed as shown inin Table 1.
Table 2 provides additional historical data on the number of states and number of seats affected provides additional historical data on the number of states and number of seats affected
by each apportionment since 1910. by each apportionment since 1910.
The map i The map in Figure 2 ~~il ustrates~~illustrates changes in states’ ideal district size and changes in the number of changes in states’ ideal district size and changes in the number of
House seats House seats ~~al ocated~~allocated to each state between the 1990 and 2020 apportionments. Regional patterns to each state between the 1990 and 2020 apportionments. Regional patterns
of population change observed following previous censuses continued in 2020, as the percentage of population change observed following previous censuses continued in 2020, as the percentage
of House seats distributed across the Northeast and Midwest regions decreased, and the of House seats distributed across the Northeast and Midwest regions decreased, and the
percentage of House seats distributed across the South and West regions increased.5 California percentage of House seats distributed across the South and West regions increased.5 California
had the largest House delegation following the 2020 census, with 52 seats; Alaska, Delaware, had the largest House delegation following the 2020 census, with 52 seats; Alaska, Delaware,
North Dakota, South Dakota, Vermont, and Wyoming each had a single House seat.6 North Dakota, South Dakota, Vermont, and Wyoming each had a single House seat.6

~~1 T he~~ 1 The apportionment population reflects the total resident population in each of the 50 states, including minors, apportionment population reflects the total resident population in each of the 50 states, including minors,
noncitizens, Armed Forces personnel/dependents living overseas, and federalnoncitizens, Armed Forces personnel/dependents living overseas, and federal civilian employees/dependents living civilian employees/dependents living
overseas; for more information see U.S. Censusoverseas; for more information see U.S. Census Bureau,Bureau, “ “Congressional Apportionment: Frequently Asked Questions,” Congressional Apportionment: Frequently Asked Questions,”
January 8, 2021, at https://www.census.gov/topics/public-sector/congressional-January 8, 2021, at https://www.census.gov/topics/public-sector/congressional-~~apport ionment~~apportionment/about/faqs.html. For /about/faqs.html. For
2020 census results, see U.S.2020 census results, see U.S. ~~Census Bureau, “T able~~ Census Bureau, “Table A. Apportionment Population, Resident Population, and Overseas A. Apportionment Population, Resident Population, and Overseas
Population: 2020 Census and 2010 Census,”Population: 2020 Census and 2010 Census,” 2020 Census Apportionment Results, April 26, 2021, at , April 26, 2021, at
https://www2.census.gov/programs-surveys/decennial/2020/data/apportionment/apportionment-2020-tableA.xlsx https://www2.census.gov/programs-surveys/decennial/2020/data/apportionment/apportionment-2020-tableA.xlsx
2 Colorado had 2 Colorado had the smallest increase in average district population size after the 2020 census, increasing by 2,067 the smallest increase in average district population size after the 2020 census, increasing by 2,067
individualsindividuals on average per district when compared to the 2010 census. West Virginiaon average per district when compared to the 2010 census. West Virginia had the largest increase in had the largest increase in
average district population size after the 2020 census, increasing by 277,585 individuals on average per district when average district population size after the 2020 census, increasing by 277,585 individuals on average per district when
compared to the 2010 census. CRScompared to the 2010 census. CRS calculations basedcalculations based on information provided in U.S. Censuson information provided in U.S. Census Bureau,Bureau, Historical
~~Apportionm ent~~Apportionment Data (1910-2020), April 26, 2021, at https://www.census.gov/data/tables/time-series/dec/, April 26, 2021, at https://www.census.gov/data/tables/time-series/dec/
apportionmentapportionment -data-text.html. -data-text.html.
3 Montana’s average district population size decreased3 Montana’s average district population size decreased by 451,712 individuals, Oregon’s average district population by 451,712 individuals, Oregon’s average district population
size decreasedsize decreased by by 62,804 individuals, and Mississippi’s62,804 individuals, and Mississippi’s average district population size decreasedaverage district population size decreased by 3,581 individuals by 3,581 individuals
after the 2020 census. CRSafter the 2020 census. CRS calculations basedcalculations based on information provided in U.S. Censuson information provided in U.S. Census Bureau,Bureau, Historical
~~Apportionm ent~~Apportionment Data (1910-2020), April 26, 2021, at https://www.census.gov/data/tables/time-series/dec/, April 26, 2021, at https://www.census.gov/data/tables/time-series/dec/
apportionmentapportionment -data-text.html. -data-text.html.
4 U.S. 4 U.S. ~~Census~~ Census Bureau,Bureau, Historical Apportionment Data (1910-2020), at https://www.census.gov/data/tables/time-series/, at https://www.census.gov/data/tables/time-series/
dec/apportionment-data-text.html. Sedec/apportionment-data-text.html. See Table 3 for3 ~~for~~ further information on average congressional district sizes since further information on average congressional district sizes since
1910. 1910.
5 See5 See U.S.U.S. Census,Census, “Presentation: 2020 Census Apportionment News Conference,” “Presentation: 2020 Census Apportionment News Conference,” 2020 Census Apportionment Counts
Press Kit, April 26, 2021, at https://www.census.gov/content/dam/Census/newsroom/press-kits/2021/20210426-, April 26, 2021, at https://www.census.gov/content/dam/Census/newsroom/press-kits/2021/20210426-
apportionmentapportionment -presentation.pdf; see also Paul Mackun and Steven Wilson, -presentation.pdf; see also Paul Mackun and Steven Wilson, Population Distribution and Change:
2000:2010, U.S. Census, U.S. Census Bureau,Bureau, Report Number C2010BR-01, Washington, DC, March 2011, at Report Number C2010BR-01, Washington, DC, March 2011, at
https://www.census.gov/prod/cen2010/briefs/c2010br-01.pdf; and Kristen D. Burnett, https://www.census.gov/prod/cen2010/briefs/c2010br-01.pdf; and Kristen D. Burnett, Congressional ~~Apportionm ent~~Apportionment:
2010 Census Briefs, U.S., U.S. ~~Census~~ Census Bureau,Bureau, Report Number C2010BR-08, Washington, DC, November 2011, pp. 4Report Number C2010BR-08, Washington, DC, November 2011, pp. 4 -5, at -5, at
https://www.census.gov/content/dam/Census/library/publications/2011/dec/c2010br-08.pdf. Historical information https://www.census.gov/content/dam/Census/library/publications/2011/dec/c2010br-08.pdf. Historical information
dating back to 1910 on state seat gains and losses,dating back to 1910 on state seat gains and losses, as wellas well as the average number of people per representative in each as the average number of people per representative in each
state, is available from U.S. Censusstate, is available from U.S. Census Bureau,Bureau, Historical ~~Apportionm ent~~Apportionment Data (1910-2020), April 26, 2021, at , April 26, 2021, at
https://www.census.gov/data/tables/time-series/dec/apportionmenthttps://www.census.gov/data/tables/time-series/dec/apportionment -data-text.html. -data-text.html.
6 U.S. Census Bureau, “Table~~6 U.S. Census Bureau, “T able~~ 1. Apportionment Population and Number of Representatives by State: 2020 Census,” 1. Apportionment Population and Number of Representatives by State: 2020 Census,”
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Table 1. Loss or Gain of U.S. House Seats in States Following 2020 Census
Lost U.S. House Seats
Gained U.S. House Seats
State
Seat Change
State
Seat Change
California California
-1 -1
Colorado Colorado
+1 +1
Il inois Il inois
-1 -1
Florida Florida
+1 +1
Michigan Michigan
-1 -1
Montana Montana
+1 +1
New York New York
-1 -1
North Carolina North Carolina
+1 +1
Ohio Ohio
-1 -1
Oregon Oregon
+1 +1
Pennsylvania Pennsylvania
-1 -1
Texas Texas
+2 +2
West Virginia West Virginia
-1 -1

Source: U.S. Census Bureau, “Table D1. Number of Seats Gained and Lost in U.S.U.S. Census Bureau, “Table D1. Number of Seats Gained and Lost in U.S. House of Representatives by House of Representatives by
State: 2020 Census,” State: 2020 Census,” 2020 Census Apportionment Results, April, April 26, 2021, at https://www2.census.gov/programs-26, 2021, at https://www2.census.gov/programs-
surveys/decennial/2020/data/apportionment/apportionment-2020-tableD.xlsx. surveys/decennial/2020/data/apportionment/apportionment-2020-tableD.xlsx.
Table 2. Scope of Apportionment Changes, 1910-2020
Total States
House Seats
States Losing
States Gaining
Affected By
Affected by
Census Year
Seats
Seats
Apportionment
Apportionment
2020 2020
7 (14.0%) 7 (14.0%)
6 (12.0%) 6 (12.0%)
13 (26.0%) 13 (26.0%)
7 (1.6%) 7 (1.6%)
2010 2010
10 (20.0%) 10 (20.0%)
8 (16.0%) 8 (16.0%)
18 (36.0%) 18 (36.0%)
12 (2.8%) 12 (2.8%)
2000 2000
10 (20.0%) 10 (20.0%)
8 (16.0%) 8 (16.0%)
18 (36.0%) 18 (36.0%)
12 (2.8%) 12 (2.8%)
1990 1990
13 (26.0%) 13 (26.0%)
8 (16.0%) 8 (16.0%)
21 (42.0%) 21 (42.0%)
19 (4.4%) 19 (4.4%)
1980 1980
10 (20.0%) 10 (20.0%)
11 (22.0%) 11 (22.0%)
21 (42.0%) 21 (42.0%)
17 (3.9%) 17 (3.9%)
1970 1970
9 (18.0%) 9 (18.0%)
5 (10.0%) 5 (10.0%)
14 (28.0%) 14 (28.0%)
11 (2.5%) 11 (2.5%)
~~1960a~~1960a
16 (32.0%) 16 (32.0%)
10 (20.0%) 10 (20.0%)
26 (52.0%) 26 (52.0%)
21 (4.8%) 21 (4.8%)
~~1950b~~1950b
9 (18.8%) 9 (18.8%)
7 (14.6%) 7 (14.6%)
16 (33.3%) 16 (33.3%)
14 (3.2%) 14 (3.2%)
~~1940b~~1940b
9 (18.8%) 9 (18.8%)
7 (14.6%) 7 (14.6%)
16 (33.3%) 16 (33.3%)
9 (2.1%) 9 (2.1%)
~~1930b~~1930b
21 (43.8%) 21 (43.8%)
13 (27.1%) 13 (27.1%)
34 (70.8%) 34 (70.8%)
27 (6.2%) 27 (6.2%)
~~1920c~~1920c
— —
— —
— —
— —
~~1910d~~1910d
0 (0.0%) 0 (0.0%)
25 (54.3%) 25 (54.3%)
25 (54.3%) 25 (54.3%)
47 (10.9%) 47 (10.9%)
Source: U.S. Census Bureau, U.S. Census Bureau, Historical ~~Apportionment~~ Apportionment Data Map,, April 26, 2021, at https://www.census.gov/April 26, 2021, at https://www.census.gov/
library/visualizations/interactive/historical-apportionment-data-map.html.library/visualizations/interactive/historical-apportionment-data-map.html.

~~2020 Census Apportionm ent~~ 2020 Census Apportionment Results, April 26, 2021, April 26, 2021, at https://www2.census.gov/programs-surveys/decennial/2020/ at https://www2.census.gov/programs-surveys/decennial/2020/
data/apportionment/apportionment-2020-table01.xlsx. data/apportionment/apportionment-2020-table01.xlsx.
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Apportionment and Redistricting Process for the U.S. House of Representatives

a. The 1960 apportionment was the first to include a. The 1960 apportionment was the first to include ~~Hawai~~ Hawaii and Alaska,and Alaska, which became states in 1959which became states in 1959 . .
b. Apportionments between 1930 and 1950 occurred with 48 states. b. Apportionments between 1930 and 1950 occurred with 48 states.
c. No apportionment occurred after the 1920 census. c. No apportionment occurred after the 1920 census.
d. The 1910 apportionment occurred with a House size of 433 and 46 states. Two seats wered. The 1910 apportionment occurred with a House size of 433 and 46 states. Two seats were added to the added to the
House once Arizona and New Mexico became states in 1912. House once Arizona and New Mexico became states in 1912.
Figure 2. Changes to Average District Apportionment Population Sizes and House
Seats Over Last Four Apportionment Cycles, 1990-2020

Source: CRS compilation of apportionment population data for 1990 and 2020 from the U.S. Census Bureau. CRS compilation of apportionment population data for 1990 and 2020 from the U.S. Census Bureau.
Graphic created by Amber Hope Wilhelm,Graphic created by Amber Hope Wilhelm, CRS Visual Information Specialist. CRS Visual Information Specialist.
Federal Requirements/Guidelines for Reapportionment: History
and Current Policy
The constitutional requirements for representation in the House based on state population size are The constitutional requirements for representation in the House based on state population size are
provided in Article I, Section 2, as amended by Section 2 of the Fourteenth Amendment.7 Article provided in Article I, Section 2, as amended by Section 2 of the Fourteenth Amendment.7 Article
I, Section 2, specified the first apportionment of seats for the House of Representatives,8 and it I, Section 2, specified the first apportionment of seats for the House of Representatives,8 and it
also includes some standards for subsequent reapportionments. Article I, Section 2, requires that also includes some standards for subsequent reapportionments. Article I, Section 2, requires that
the national population be counted at least once every 10 years in order to distribute House seats the national population be counted at least once every 10 years in order to distribute House seats
across states. Broad parameters for the number of House Members are also contained in Article I, across states. Broad parameters for the number of House Members are also contained in Article I,

7 Article I, Section 2, clause7 Article I, Section 2, clause 3, originally stated, “Representatives and direct 3, originally stated, “Representatives and direct ~~T axes~~Taxes shall be apportioned among the shall be apportioned among the
several States whichseveral States which may be includedmay be included within this Union, according to their respective Numbers, which shall be within this Union, according to their respective Numbers, which shall be
determined by addingdetermined by adding ~~t o~~ to the whole Number the whole Number of free Persons, includingof free Persons, including those boundthose bound to Service for a to Service for a ~~T erm~~Term of Years, and of Years, and
excludingexcluding Indians not taxed, three fifths of all other Persons.” Following the abolition of slavery, the Fourteenth Indians not taxed, three fifths of all other Persons.” Following the abolition of slavery, the Fourteenth
Amendment, Section 2, states, “Amendment, Section 2, states, “ Representatives shall be apportioned among the several States according to their Representatives shall be apportioned among the several States according to their
respective numbers, counting the whole number of persons in each State, excludingrespective numbers, counting the whole number of persons in each State, excluding Indians not taxed.Indians not taxed. ” For more ” For more
information, see Office of the Historian, U.S. House of Representatives, “information, see Office of the Historian, U.S. House of Representatives, “ ~~Propo rtional~~Proportional Representation,” at Representation,” at
https://history.house.gov/Institution/Origins-Development/Proportional-Representation/.https://history.house.gov/Institution/Origins-Development/Proportional-Representation/.
8 Article 1, Section 2, provides that a first census 8 Article 1, Section 2, provides that a first census ~~would~~ would be taken within three years of the first meeting of Congress, be taken within three years of the first meeting of Congress,
and until the population was formally enumerated by a census,and until the population was formally enumerated by a census, there wouldthere would be 65 Housebe 65 House Members, allocated among Members, allocated among
NewNew Hampshire (3), Massachusetts (8), Rhode Island (1), Connecticut (5), New York (6), New Jersey (4), Hampshire (3), Massachusetts (8), Rhode Island (1), Connecticut (5), New York (6), New Jersey (4),
Pennsylvania (8), Delaware (1), Maryland (6), VirginiaPennsylvania (8), Delaware (1), Maryland (6), Virginia (10), North Carolina (5), South Carolina (5), and Georgia(10), North Carolina (5), South Carolina (5), and Georgia (3).(3).
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Section 2: there can be no more than one Representative for every 30,000 persons, provided that Section 2: there can be no more than one Representative for every 30,000 persons, provided that
each state receives at least one Representative. each state receives at least one Representative.
Federal statute establishes a number of other elements of the apportionment process, including Federal statute establishes a number of other elements of the apportionment process, including
how to count the population every 10 years via the decennial census; how many seats are in the how to count the population every 10 years via the decennial census; how many seats are in the
House; how those House seats are divided across states; and certain related administrative details. House; how those House seats are divided across states; and certain related administrative details.
In the 19th century, Congress often passed measures each decade to address those factors In the 19th century, Congress often passed measures each decade to address those factors
~~specifical y~~specifically for the next upcoming census and reapportionment. By the early 20th century, for the next upcoming census and reapportionment. By the early 20th century,
however, Congress began to create legislation to standardize the process and apply it to however, Congress began to create legislation to standardize the process and apply it to al
all subsequent censuses and reapportionments, unless modified by later acts.9subsequent censuses and reapportionments, unless modified by later acts.9
One example of such legislation was the permanent authorization of the U.S. Census Bureau in One example of such legislation was the permanent authorization of the U.S. Census Bureau in
1902,10 which helped establish a recurring decennial census process and timeline. Other 1902,10 which helped establish a recurring decennial census process and timeline. Other
~~legislation~~ legislation established the current number of 435 House seats;11 this number was first used established the current number of 435 House seats;11 this number was first used
following the 1910 census and subsequently became fixed under the Permanent Apportionment following the 1910 census and subsequently became fixed under the Permanent Apportionment
Act of 1929.12 Congress also created a more general reapportionment formula and process to Act of 1929.12 Congress also created a more general reapportionment formula and process to
redistribute seats across states. The timeline for congressional reapportionment and current redistribute seats across states. The timeline for congressional reapportionment and current
method for method for ~~al ocating~~allocating seats among states were contained in the Apportionment Act of 1941, seats among states were contained in the Apportionment Act of 1941,
which would then apply to every reapportionment cycle, beginning with the one following the which would then apply to every reapportionment cycle, beginning with the one following the
1950 census.13 The size of the House, method for reapportionment, and timeline for 1950 census.13 The size of the House, method for reapportionment, and timeline for
reapportionment are codified in 2 U.S.C. §2a and are further detailed in the section below, reapportionment are codified in 2 U.S.C. §2a and are further detailed in the section below,
alongside the relevant census procedures codified in Title 13 of the alongside the relevant census procedures codified in Title 13 of the U.S. Code. .
Reapportionment Method and Timeline
The apportionment steps detailed below are also summarized by the timelineThe apportionment steps detailed below are also summarized by the timeline inin Figure 1. This This
information is representative of the typical census, apportionment, and redistricting processes, but information is representative of the typical census, apportionment, and redistricting processes, but
the Coronavirus Disease 2019 (COVID-19) pandemic affected 2020 census field operations and the Coronavirus Disease 2019 (COVID-19) pandemic affected 2020 census field operations and
delivery of apportionment figures; for further discussion of these changes and delays, see CRS In delivery of apportionment figures; for further discussion of these changes and delays, see CRS In
Focus IF11486, Focus IF11486, 2020 Census Fieldwork Delayed by COVID-19 and CRS Insight IN11360, and CRS Insight IN11360,
Apportionment and Redistricting Following the 2020 Census. .
Under federal law, April Under federal law, April 1 in any year ending in “0” marks the official decennial census date and 1 in any year ending in “0” marks the official decennial census date and
the beginning of the population counting process.14 The U.S. Census Bureau calculates the the beginning of the population counting process.14 The U.S. Census Bureau calculates the

9 For one overview of provisions contained in various apportionment acts, see Emanuel Celler,9 For one overview of provisions contained in various apportionment acts, see Emanuel Celler, “Congressional “Congressional
Apportionment—Past, Present, and Future,” Apportionment—Past, Present, and Future,” Law and ~~Contem porary Problem s~~Contemporary Problems, vol. 17, no. 2 (Spring 1952), pp. 268, vol. 17, no. 2 (Spring 1952), pp. 268 --
275, at https://scholarship.law.duke.edu/lcp/vol17/iss2/3/. Copies of past apportionment acts (1790275, at https://scholarship.law.duke.edu/lcp/vol17/iss2/3/. Copies of past apportionment acts (1790 -1941) are available -1941) are available
from the U.S. Censusfrom the U.S. Census ~~Bureau~~ Bureau at https://www.census.gov/history/www/reference/apportionmentat https://www.census.gov/history/www/reference/apportionment . .
10 13 U.S.C. 10 13 U.S.C. §2 note. §2 note.
11 11 ~~T his excludes~~ This excludes the nonvoting House seats held by Delegates and the Resident Commissioner; Article I, Section 2, and the nonvoting House seats held by Delegates and the Resident Commissioner; Article I, Section 2, and
resulting apportionment practices, only address Representatives from U.S. states. resulting apportionment practices, only address Representatives from U.S. states.
12 The~~12 T he~~ 1910 apportionment act (P.L. 62-5, August 8, 1911, 37 Stat. 13, Ch. 5) set the House size 1910 apportionment act (P.L. 62-5, August 8, 1911, 37 Stat. 13, Ch. 5) set the House size at 433, but provided at 433, but provided
for the addition of one seat each to Newfor the addition of one seat each to New Mexico and Arizona, if they became states before the next apportionment, Mexico and Arizona, if they became states before the next apportionment,
which they did. which they did. ~~T he~~The next enacted apportionment bill was next enacted apportionment bill was the Permanent Apportionment Act of 1929 (P.L. 71-13, June the Permanent Apportionment Act of 1929 (P.L. 71-13, June
18, 1929, 26 Stat. 21, Ch. 28), which preserved the methods of the preceding apportionment for subsequent 18, 1929, 26 Stat. 21, Ch. 28), which preserved the methods of the preceding apportionment for subsequent
apportionments. The enabling acts for Alaska and Hawaiiapportionments. The enabling acts for Alaska and Hawaii statehood provided temporary increases in the size of the statehood provided temporary increases in the size of the
HouseHouse to provide seats for the new states until the next regular reapportionment, and as a result, the House had 437 to provide seats for the new states until the next regular reapportionment, and as a result, the House had 437
seats between 1959 and 1962. Seeseats between 1959 and 1962. See P.L. 85P.L. 85 -508, July 7, 1958; P.L. 86-3, March 18, 1959, 73 Stat. 4. -508, July 7, 1958; P.L. 86-3, March 18, 1959, 73 Stat. 4.
13 P.L. 77-291, November 15, 1941, 55 Stat. 761, Ch. 470. Similar provisions were contained in the Permanent 13 P.L. 77-291, November 15, 1941, 55 Stat. 761, Ch. 470. Similar provisions were contained in the Permanent
Reapportionment Act of 1929. Reapportionment Act of 1929.
14 13 U.S.C.14 13 U.S.C. §141(a). For additional information on the census process, see CRS§141(a). For additional information on the census process, see CRS Report R44788, Report R44788, The Decennial
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apportionment population for the United States from the information it collects in the decennial apportionment population for the United States from the information it collects in the decennial
census and certain administrative records.15 The apportionment population reflects the total census and certain administrative records.15 The apportionment population reflects the total
resident population in each of the 50 states, including minors and noncitizens, plus Armed Forces resident population in each of the 50 states, including minors and noncitizens, plus Armed Forces
personnel/dependents living overseas and federal civilian employees/dependents living personnel/dependents living overseas and federal civilian employees/dependents living
overseas.16 The Secretary of Commerce must report the apportionment population to the President overseas.16 The Secretary of Commerce must report the apportionment population to the President
within nine months of the census date (by December 31 of the year ending in “0”).17 In past years, within nine months of the census date (by December 31 of the year ending in “0”).17 In past years,
the Census Bureau has released apportionment counts to the public at about the same time they the Census Bureau has released apportionment counts to the public at about the same time they
are presented to the President.18are presented to the President.18
Under requirements in the Constitution, each state must receive at least one House Under requirements in the Constitution, each state must receive at least one House
Representative, and under statute, the current House size is set at 435 seats.19 To determine how Representative, and under statute, the current House size is set at 435 seats.19 To determine how
the 51st through 435th seats are distributed across the 50 states, a mathematical approach known as the 51st through 435th seats are distributed across the 50 states, a mathematical approach known as
the the method of equal proportions is used, which is specified in statute.20 is used, which is specified in statute.20 ~~Essential y~~Essentially, under this , under this
method, the “next” House seat availablemethod, the “next” House seat available is apportioned to the state ranked highest on a is apportioned to the state ranked highest on a priority
list. The priority list rankings are calculated by taking each state’s apportionment population from . The priority list rankings are calculated by taking each state’s apportionment population from
the most recent census, and multiplying it by a series of values. The multipliers used are the the most recent census, and multiplying it by a series of values. The multipliers used are the
reciprocals of the geometric means between every pair of consecutive whole numbers, with those reciprocals of the geometric means between every pair of consecutive whole numbers, with those
whole numbers representing House seats to be apportioned.21 The resulting priority values are whole numbers representing House seats to be apportioned.21 The resulting priority values are
ordered from largest to ordered from largest to ~~smal est~~smallest, and with the House size set at 435, the states with the top 385 , and with the House size set at 435, the states with the top 385
priority values receive the availablepriority values receive the available seats. See seats. See thethe Appendix for additional information on the for additional information on the
method of equal proportions and other methods proposed or used in previous apportionments. method of equal proportions and other methods proposed or used in previous apportionments.
The President then transmits a statement to Congress showing (1) “the whole number of persons The President then transmits a statement to Congress showing (1) “the whole number of persons
in each State,” as determined by the decennial census and certain administrative records; and (2) in each State,” as determined by the decennial census and certain administrative records; and (2)
the resulting number of Representatives each state would be entitled to under an apportionment, the resulting number of Representatives each state would be entitled to under an apportionment,
given the existing number of Representatives and using the method of equal proportions. The given the existing number of Representatives and using the method of equal proportions. The
President submits this statement to Congress within the first week of the first regular session of President submits this statement to Congress within the first week of the first regular session of

Census: Issues for 2020; and CRS; and CRS In FocusIn Focus IF11015, IF11015, The 2020 Decennial Census: Overview and Issues. .
15 13 U.S.C. 15 13 U.S.C. §141(b). §141(b).
16 For further discussion16 For further discussion of who is includedof who is included in apportionment population counts, see U.S. Censusin apportionment population counts, see U.S. Census Bureau, Bureau,
“Congressional Apportionment: Frequently Asked Questions,” August“Congressional Apportionment: Frequently Asked Questions,” August 26, 2015, at https://www.census.gov/topics/26, 2015, at https://www.census.gov/topics/
public-sector/congressional-apportionment/about/faqs.html. public-sector/congressional-apportionment/about/faqs.html.
17 13 U.S.C. 17 13 U.S.C. §141(b). §141(b).
18 For example, see U.S.18 For example, see U.S. ~~Census~~ Census Bureau,Bureau, “U.S. Census“U.S. Census ~~Bureau~~ Bureau Announces 2010 CensusAnnounces 2010 Census Population Counts Population Counts
Apportionment Counts Delivered to President,” press release, December 21, 2010, at https://www.census.gov/Apportionment Counts Delivered to President,” press release, December 21, 2010, at https://www.census.gov/
newsroom/releases/archives/2010_census/cb10-cn93.html. newsroom/releases/archives/2010_census/cb10-cn93.html.
19 Permanent Apportionment Act of 1929, P.L. 71-13, June 18, 1929, 26 Stat. 21, Ch. 28. 19 Permanent Apportionment Act of 1929, P.L. 71-13, June 18, 1929, 26 Stat. 21, Ch. 28.
20 P.L. 77-291, November 15, 1941, 55 Stat. 761, Ch. 470. 20 P.L. 77-291, November 15, 1941, 55 Stat. 761, Ch. 470. ~~T he~~The method of equal proportions is sometimes referred to as is sometimes referred to as
the the Huntington-Hill ~~m ethod~~method. Prior to the 1941 act, other apportionment methods could be. Prior to the 1941 act, other apportionment methods could be used;used; one suchone such alternative alternative
usedused in several reapportionments was the in several reapportionments was the Webster ~~m ethod~~ method. Generally, these apportionment methods vary in how they . Generally, these apportionment methods vary in how they
approach fractional seat entitlements and what rounding points should beapproach fractional seat entitlements and what rounding points should be ~~used~~ used in order to distribute those fractions of in order to distribute those fractions of
seats across states. For a discussionseats across states. For a discussion of alternate mathematical approaches, see U.S. Censusof alternate mathematical approaches, see U.S. Census Bureau,Bureau, “ “Methods of Methods of
Apportionment,” July 18, 2017, at https://www.census.gov/history/www/reference/apportionment/Apportionment,” July 18, 2017, at https://www.census.gov/history/www/reference/apportionment/
methods_of_apportionment.html; and Laurence F. Schmeckebier,methods_of_apportionment.html; and Laurence F. Schmeckebier, ~~“ T he~~ “The Method of Equal Proportions,” Method of Equal Proportions,” Law and
~~Contem porary Problem s~~Contemporary Problems, vol. 17, no. 2 (Spring 1952), pp. 302, vol. 17, no. 2 (Spring 1952), pp. 302 -313. -313.
21 A geometric mean is the square 21 A geometric mean is the square ~~root~~ root of the product of two successiveof the product of two successive numbers multiplied by each other; the numbers multiplied by each other; the
reciprocal of a geometric mean is 1 dividedreciprocal of a geometric mean is 1 divided by the geometric mean. by the geometric mean. ~~T o~~To find the “multiplier” for each state’s second find the “multiplier” for each state’s second
seat, for example, the geometric mean of 1 and 2 wouldseat, for example, the geometric mean of 1 and 2 would be be used;used; 1 multiplied by 2 equals1 multiplied by 2 equals 2, and the square2, and the square root of 2 is root of 2 is
1.41452. 1.41452. ~~T he~~The reciprocal of this geometric mean would be reciprocal of this geometric mean would be 1 divided1 divided by 1.41452, or 0.70711. For discussion on the by 1.41452, or 0.70711. For discussion on the
method of equalmethod of equal proportions, and tables with multipliers and priority values for previous proportions, and tables with multipliers and priority values for previous ~~ap portionments~~apportionments, see U.S. , see U.S.
CensusCensus Bureau,Bureau, “Computing Apportionment,” “Computing Apportionment,” Congressional Apportionment, February 4, 2013, at , February 4, 2013, at
https://www.census.gov/population/apportionment/abouthttps://www.census.gov/population/apportionment/about /computing.html. /computing.html.
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the next Congress ( the next Congress (~~typical y~~typically, early January of a year ending in “1”).22 Within 15 calendar days of , early January of a year ending in “1”).22 Within 15 calendar days of
receiving the President’s statement, the Clerk of the House sends each state governor a certificate receiving the President’s statement, the Clerk of the House sends each state governor a certificate
indicating the number of Representatives the state is entitled to. Each state receives the number of indicating the number of Representatives the state is entitled to. Each state receives the number of
Representatives noted in the President’s statement for its House delegation, beginning at the start Representatives noted in the President’s statement for its House delegation, beginning at the start
of the next session of Congress (of the next session of Congress (~~typical y~~typically, early January of a year ending in “3”)., early January of a year ending in “3”).
States may then engage in their own redistricting processes, which vary based on state laws. States may then engage in their own redistricting processes, which vary based on state laws.
Federal law contains requirements for how apportionment changes Federal law contains requirements for how apportionment changes ~~wil~~ will apply to states in the apply to states in the
event that any congressional elections occur between a reapportionment and the completion of a event that any congressional elections occur between a reapportionment and the completion of a
state’s redistricting process. In these instances, states with the same number of House seats would state’s redistricting process. In these instances, states with the same number of House seats would
use the existing congressional districts to elect Representatives; states with more seats than use the existing congressional districts to elect Representatives; states with more seats than
districts would elect a Representative for the “new” seat through an at-large election and use districts would elect a Representative for the “new” seat through an at-large election and use
existing districts for the other seats; and states with fewer seats than districts would elect existing districts for the other seats; and states with fewer seats than districts would elect al
all Representatives through an at-large election.23 Representatives through an at-large election.23
Redistricting Process24
Congressional redistricting involves creating or redrawing geographic boundaries for U.S. House Congressional redistricting involves creating or redrawing geographic boundaries for U.S. House
districts within a state. Redistricting procedures are largely determined by state law and vary districts within a state. Redistricting procedures are largely determined by state law and vary
across states, but states must comply with certain parameters established by federal statute and across states, but states must comply with certain parameters established by federal statute and
court decisions. In general, there is variation among states regarding the practice of drawing court decisions. In general, there is variation among states regarding the practice of drawing
districts and which decisionmakers are involved in the process. Across states, there are some districts and which decisionmakers are involved in the process. Across states, there are some
common standards and criteria for districts, some of which reflect values that are commonly common standards and criteria for districts, some of which reflect values that are commonly
thought of as traditional districting practices. Districting criteria may result either from shared thought of as traditional districting practices. Districting criteria may result either from shared
expectations and precedent regarding what districts should be like, or they may result from expectations and precedent regarding what districts should be like, or they may result from
certain standards established by current federal statute and court decisions. These criteria certain standards established by current federal statute and court decisions. These criteria
~~typical y~~typically reflect a goal of enabling “fair” representation for reflect a goal of enabling “fair” representation for al all residents, rather than residents, rather than ~~al owing~~
allowing arbitrary, or discriminatory, map lines.25 arbitrary, or discriminatory, map lines.25
Redistricting efforts intended to unfairly favor one group’s interests over another’s are commonly Redistricting efforts intended to unfairly favor one group’s interests over another’s are commonly
referred to as referred to as gerrymandering.26 .26 Packing and and cracking are two common terms that describe such are two common terms that describe such
districts, but there are various ways in which district boundaries might be designed to advantage districts, but there are various ways in which district boundaries might be designed to advantage
or disadvantage certain groups of voters. or disadvantage certain groups of voters. Packing describes district boundaries that are drawn to describes district boundaries that are drawn to
concentrate individuals who are thought to share similar voting behaviors into certain districts. concentrate individuals who are thought to share similar voting behaviors into certain districts.
~~Concentrating prospective voters with shared preferences can result in a large number of “wasted~~

22 P.L. 77-291, November 15, 1941, 55 Stat. 761, Ch. 470. 22 P.L. 77-291, November 15, 1941, 55 Stat. 761, Ch. 470. ~~T he~~The statute is written to apply to the first regular session of statute is written to apply to the first regular session of
the 82nd Congress “the 82nd Congress “ and of each fifth Congress thereafter.” and of each fifth Congress thereafter.”
23 2 U.S.C. 23 2 U.S.C. §2a(c). §2a(c).
24 24 ~~T his~~This report is not intended to be a legal report is not intended to be a legal analysis. For additional information on redistricting law, seeanalysis. For additional information on redistricting law, see ~~CRS~~ CRS Legal Sidebar LSB10639, Congressional Redistricting 2021: Legal Framework, CRS Report Report
R44199, R44199, Congressional Redistricting: Legal and Constitutional Issues;, and CRS and CRS Report R44798, Report R44798, Congressional
Redistricting Law: Background and Recent Court Rulings. .
25 For further discussion,25 For further discussion, see Jeanne C. Fromer, “An Exercise in Line-Drawing:see Jeanne C. Fromer, “An Exercise in Line-Drawing: Deriving and MeasuringDeriving and Measuring Fairness in Fairness in
Redistricting,” Redistricting,” Georgetown Law Journal, vol. 93 (2004-2005), pp. 1547-1623. , vol. 93 (2004-2005), pp. 1547-1623.
26 Michael Wines, “What Is Gerrymandering? What If the Supreme Court Bans26 Michael Wines, “What Is Gerrymandering? What If the Supreme Court Bans It?” It?” New York Times, March 26, 2019, , March 26, 2019,
at https://www.nytimes.com/2019/03/26/us/whatat https://www.nytimes.com/2019/03/26/us/what -is-gerrymandering.html; John O’Loughlin, “-is-gerrymandering.html; John O’Loughlin, “ ~~T he~~The Identification and Identification and
Evaluation of Racial Gerrymandering,” Evaluation of Racial Gerrymandering,” Annals of the Association of American Geographers, vol. 72, no. 2 (June 1982), , vol. 72, no. 2 (June 1982),
pp. 165-184; John N. Friedman and Richardpp. 165-184; John N. Friedman and Richard T T. Holden, “. Holden, “ ~~T he~~The Rising Incumbent Reelection Rate: What’s Rising Incumbent Reelection Rate: What’s
Gerrymandering Got to Do With It?” Gerrymandering Got to Do With It?” Journal of Politics, vol. 71, no. 2 (April 2009), pp. 593-611; CRS Legal Sidebar , vol. 71, no. 2 (April 2009), pp. 593-611; CRS Legal Sidebar
LSB10164, LSB10164, Partisan ~~Gerrym andering: Suprem e~~Gerrymandering: Supreme Court Provides Guidance on Standing and Maintains Legal Status
Quo. .
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Concentrating prospective voters with shared preferences can result in a large number of “wasted votes” for these districts, as their Representatives votes” for these districts, as their Representatives ~~wil~~ will often be elected by a supermajority that far often be elected by a supermajority that far
exceeds the number of votes required for a candidate to win. exceeds the number of votes required for a candidate to win. Cracking may be thought of as the may be thought of as the
opposite of packing, and occurs when individuals who are thought to share similar voting opposite of packing, and occurs when individuals who are thought to share similar voting
preferences are deliberately dispersed across a number of districts. This approach dilutes the preferences are deliberately dispersed across a number of districts. This approach dilutes the
voting strength of a group and can prevent its preferred candidates from receiving a majority of voting strength of a group and can prevent its preferred candidates from receiving a majority of
the vote in any district. the vote in any district.
For some states, redistricting following an apportionment may be necessary to account for House For some states, redistricting following an apportionment may be necessary to account for House
seats gained or lost based on the most recent census population count.27 seats gained or lost based on the most recent census population count.27 ~~General y~~Generally, however, , however,
states with multiple congressional districts engage in redistricting following an apportionment in states with multiple congressional districts engage in redistricting following an apportionment in
order to ensure that the population size of each district remains approximately equal under the order to ensure that the population size of each district remains approximately equal under the
equality standard or “one person, one vote” principle (discussed underequality standard or “one person, one vote” principle (discussed under “Population Equality”
below). Some states might make additional changes to district boundaries in the years following below). Some states might make additional changes to district boundaries in the years following
an initialan initial redistricting; in some instances, such changes are required by legal decisions finding redistricting; in some instances, such changes are required by legal decisions finding
that the initialthat the initial districts were improperly drawn.28 districts were improperly drawn.28
Federal Requirements/Guidelines for Redistricting: History and
Current Policy
From time to time, Congress considers legislation that would affect apportionment and From time to time, Congress considers legislation that would affect apportionment and
redistricting processes. The Constitution requires the apportionment of House seats across states redistricting processes. The Constitution requires the apportionment of House seats across states
based on population size, but it does not specify how those seats are to be distributed within each based on population size, but it does not specify how those seats are to be distributed within each
state. Most redistricting practices are determined by state constitutions or statutes, although some state. Most redistricting practices are determined by state constitutions or statutes, although some
parts of the redistricting process are affected by federal statute or judicial interpretations.29parts of the redistricting process are affected by federal statute or judicial interpretations.29
The current system of single-member districts (rather than a general ticket system, where voters The current system of single-member districts (rather than a general ticket system, where voters
could select a slate of Representatives for an entire state) is provided by 2 U.S.C. §2c.30 In could select a slate of Representatives for an entire state) is provided by 2 U.S.C. §2c.30 In
addition to requiring single-member districts, Congress has, at times, passed legislation addition to requiring single-member districts, Congress has, at times, passed legislation
addressing House district characteristics. For example, in the 1800s and early 1900s, some federal addressing House district characteristics. For example, in the 1800s and early 1900s, some federal
apportionment statutes included other standards for congressional districts, such as population apportionment statutes included other standards for congressional districts, such as population
equality or geographic compactness.31 None of these criteria is expressly contained in the current equality or geographic compactness.31 None of these criteria is expressly contained in the current
statute addressing federal apportionment.32statute addressing federal apportionment.32

27 Table 1 provides information on which states gained and lost seats following the 2020 census, provides information on which states gained and lost seats following the 2020 census, and and Table 2 provides provides
additional historical data on the number of states and House seats affected by each apportionment since 1910.additional historical data on the number of states and House seats affected by each apportionment since 1910.
~~28 CRS~~ 28 See CRS Report R44798, Report R44798, Congressional Redistricting Law: Background and Recent Court Rulings. .
29 Ibid. 29 Ibid.
30 P.L. 90-196, December 14, 1967, 81 Stat. 581. The requirement for single-member districts had previously appeared 30 P.L. 90-196, December 14, 1967, 81 Stat. 581. The requirement for single-member districts had previously appeared
in the Apportionment Act of 1842 (June 25, 1842, 5 Stat. 491). For additional history, see Erik J. Engstrom, “in the Apportionment Act of 1842 (June 25, 1842, 5 Stat. 491). For additional history, see Erik J. Engstrom, “~~T he~~The
OriginsOrigins of Single-Memberof Single-Member Districts,” ch. 3 in Districts,” ch. 3 in Partisan ~~Gerrym andering~~Gerrymandering and the Construction of ~~Am erican Dem ocracy~~American Democracy
(Ann Arbor, MI: University of Michigan Press, 2013), pp. 43(Ann Arbor, MI: University of Michigan Press, 2013), pp. 43 -55. -55.
31 Examples include31 Examples include a requirement for equala requirement for equal population size “as nearly aspopulation size “as nearly as practicable” (practicable” ( “An Act for the Apportionment “An Act for the Apportionment
of Representatives to Congress among the several States according to the ninth Census,” Februaryof Representatives to Congress among the several States according to the ninth Census,” February 2, 1872, 17 Stat. 28); 2, 1872, 17 Stat. 28);
and districts of “and districts of “ contiguous and compact territory” (“An Act Making an apportionment of Representatives in Congress contiguous and compact territory” (“An Act Making an apportionment of Representatives in Congress
among the several States underamong the several States under ~~the T welfth~~ the Twelfth Census,” January 16, 1901, 31 Stat. 733; “ Census,” January 16, 1901, 31 Stat. 733; “ An Act for the apportionment of An Act for the apportionment of
Representatives in Congress among the several States under the Representatives in Congress among the several States under the ~~T hirteenth~~Thirteenth Census, Census, ” P.L. 62-5, August” P.L. 62-5, August 8, 1911, 37 Stat. 8, 1911, 37 Stat.
13, Ch. 5). Some of these provisions appeared in several subsequent13, Ch. 5). Some of these provisions appeared in several subsequent apportionment bills. apportionment bills.
32 P.L. 77-291, November 15, 1941, 55 Stat. 761, Ch. 470. 32 P.L. 77-291, November 15, 1941, 55 Stat. 761, Ch. 470.
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Many of the other federal parameters for congressional redistricting have resulted from judicial Many of the other federal parameters for congressional redistricting have resulted from judicial
decisions.33 It is not uncommon for states to face legal decisions.33 It is not uncommon for states to face legal ~~chal enges~~challenges regarding elements of their regarding elements of their
redistricting plans.34 One analysis of the 2010 redistricting cycle, for example, found that redistricting plans.34 One analysis of the 2010 redistricting cycle, for example, found that
redistricting lawsuits had been filed in 38 states,35 and legal redistricting lawsuits had been filed in 38 states,35 and legal ~~chal enges~~challenges to congressional districts to congressional districts
in several states continued for a number of years.36 This report is not intended to be a legal in several states continued for a number of years.36 This report is not intended to be a legal
analysis. For additional information on redistricting law, see CRS analysis. For additional information on redistricting law, see CRS Legal Sidebar LSB10639, Congressional Redistricting 2021: Legal Framework, CRS Report R44199, Report R44199, Congressional
Redistricting: Legal and Constitutional Issues, and CRS Report R44798, , and CRS Report R44798, Congressional
Redistricting Law: Background and Recent Court Rulings. .
Population Equality
One area of redistricting addressed by federal standards is population equality across districts. One area of redistricting addressed by federal standards is population equality across districts.
LegislativeLegislative provisions, requiring that congressional districts “[contain] as nearly as practicable an provisions, requiring that congressional districts “[contain] as nearly as practicable an
equal number of inhabitants,” were found in federal apportionment acts between 1872 and 1911.37 equal number of inhabitants,” were found in federal apportionment acts between 1872 and 1911.37
The U.S. Supreme Court has also addressed population size variance among congressional The U.S. Supreme Court has also addressed population size variance among congressional
districts within a state, or districts within a state, or malapportionment. Under what is known as the “equality standard” or . Under what is known as the “equality standard” or
“one person, one vote” principle, the Court has found congressional districts within a state should “one person, one vote” principle, the Court has found congressional districts within a state should
be drawn to approximately equal population sizes.38 be drawn to approximately equal population sizes.38 ~~Mathematical y~~Mathematically, there are several ways in , there are several ways in
which the population difference across districts (or deviation from an ideal district size) may be which the population difference across districts (or deviation from an ideal district size) may be
expressed.39 expressed.39
These equal population standards apply only to districts within a state, not to districts across These equal population standards apply only to districts within a state, not to districts across
states. To states. To ~~il ustrate~~illustrate how district population sizes can vary across states how district population sizes can vary across states, Table 3 provides Census provides Census
Bureau estimates from 1910 to 2020 for the average district population size nationwide, as Bureau estimates from 1910 to 2020 for the average district population size nationwide, as ~~wel~~ well as as
estimates for which states had the largest and estimates for which states had the largest and ~~smal est~~smallest average district population sizes. Wide average district population sizes. Wide
variations in state populations and the U.S. Constitution’s requirement of at least one House seat variations in state populations and the U.S. Constitution’s requirement of at least one House seat
~~per state make it difficult to ensure equal district sizes across states, particularly if the size of the~~

~~33 See CRS~~ 33 See CRS Report R44798, Report R44798, Congressional Redistricting Law: Background and Recent Court Rulings, for additional , for additional
information. information.
34 Adam Mueller, “34 Adam Mueller, “~~T he~~The Implications of Legislative Power: State Constitutions, State Legislatures, and Mid-Decade Implications of Legislative Power: State Constitutions, State Legislatures, and Mid-Decade
Redistricting,” Redistricting,” Boston College Law Review, vol. 48 (2007), p. 1344. , vol. 48 (2007), p. 1344.
35 “Redistricting Lawsuits35 “Redistricting Lawsuits Relating to the 2010 Census,” Relating to the 2010 Census,” Ballotpedia, updated September 2015, at , updated September 2015, at
https://ballotpedia.org/Redistricting_lawsuits_relating_to_the_2010_Census. https://ballotpedia.org/Redistricting_lawsuits_relating_to_the_2010_Census.
36 For one listing of litigation across states for both congressional districts and 36 For one listing of litigation across states for both congressional districts and state legislative districts, see Michael Li, state legislative districts, see Michael Li,
~~T homas~~Thomas Wolf, and Annie Lo, “ Wolf, and Annie Lo, “~~T he~~The State of Redistricting Litigation,” Brennan Center for Justice, April 1, 2021, at State of Redistricting Litigation,” Brennan Center for Justice, April 1, 2021, at
https://www.brennancenter.org/blog/state-redistricting-litigation. See also “https://www.brennancenter.org/blog/state-redistricting-litigation. See also “ Redistricting LawsuitsRedistricting Lawsuits Relating to the 2010 Relating to the 2010
Census,”Census,” Ballotpedia, updated September 2015, at https://ballotpedia.org/, updated September 2015, at https://ballotpedia.org/
Redistricting_lawsuits_relating_to_the_2010_Census. Redistricting_lawsuits_relating_to_the_2010_Census. ~~T hese~~These resources provide examples of some recent legal resources provide examples of some recent legal
challenges but may not represent a comprehensive account of all cases.challenges but may not represent a comprehensive account of all cases.
37 Historical apportionment acts can be viewed 37 Historical apportionment acts can be viewed at U.S.at U.S. ~~Census~~ Census Bureau,Bureau, “Apportionment Legislation 1840-1880,” “Apportionment Legislation 1840-1880,”
History, at https://www.census.gov/history/www/reference/apportionment/apportionment_legislation_1840_-, at https://www.census.gov/history/www/reference/apportionment/apportionment_legislation_1840_-
_1880.html; U.S. Census_1880.html; U.S. Census Bureau,Bureau, “ “Apportionment Legislation 1890Apportionment Legislation 1890 -Present,” -Present,” History, at https://www.census.gov/, at https://www.census.gov/
history/www/reference/apportionment/apportionment_legislation_1890_-_present.html. history/www/reference/apportionment/apportionment_legislation_1890_-_present.html.
38 See 38 See ~~CRS~~ CRS Report R44798, Report R44798, Congressional Redistricting Law: Background and Recent Court Rulings. .
For an overview of these, and related, Supreme For an overview of these, and related, Supreme Court cases, seeCourt cases, see National Conference of State Legislatures, “National Conference of State Legislatures, “ Cases Cases
Relating to Population,” in Relating to Population,” in Redistricting and the Supreme Court: The Most Significant Cases, July 19, 2018, at , July 19, 2018, at
http://www.ncsl.org/research/redistricting/redistricting-and-the-supreme-courthttp://www.ncsl.org/research/redistricting/redistricting-and-the-supreme-court -the-most-significant-cases.aspx; also -the-most-significant-cases.aspx; also
National Conference of State Legislatures, “National Conference of State Legislatures, “ Equal Population,” in Equal Population,” in Redistricting Law 2010, December 1, 2009, ch. 3, at , December 1, 2009, ch. 3, at
http://www.ncsl.org/research/redistricting/redistricting-law-2010.aspx. http://www.ncsl.org/research/redistricting/redistricting-law-2010.aspx.
39 See 39 See National Conference of State Legislatures, “Measuring Population Equality Among Districts,” in National Conference of State Legislatures, “Measuring Population Equality Among Districts,” in Redistricting
Law 2010, December 1, 2009, pp. 23-25, at http://www.ncsl.org/research/redistricting/redistricting-law-2010.aspx. , December 1, 2009, pp. 23-25, at http://www.ncsl.org/research/redistricting/redistricting-law-2010.aspx.
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per state make it difficult to ensure equal district sizes across states, particularly if the size of the House is fixed.40 The expectation that districts in a state House is fixed.40 The expectation that districts in a state ~~wil~~ will have equal population sizes have equal population sizes
reinforces the long-standing practice that states redraw district boundaries following each U.S. reinforces the long-standing practice that states redraw district boundaries following each U.S.
Census, in order to account for the sizable population shifts that can occur within a 10-year Census, in order to account for the sizable population shifts that can occur within a 10-year
span.41span.41
Table 3. Summary of Average U.S. House District Population Sizes, 1910-2020
Apportionment
Average District
Largest Average
Smallest Average
Year
Population Size
District Population
District Population
2020 2020
761,169 761,169
990,837 (Delawar 990,837 (Delawarea)
542,704 (Montana) 542,704 (Montana)
2010 2010
710,767 710,767
994,416 ( 994,416 (~~Montanaa~~Montanaa)
527,624 (Rhode Island) 527,624 (Rhode Island)
2000 2000
646,952 646,952
905,316 ( 905,316 (~~Montanaa~~Montanaa)
495,304 (Wyomin 495,304 (Wyominga)
1990 1990
572,466 572,466
803,655 ( 803,655 (~~Montanaa~~Montanaa)
455,975 (Wyomin 455,975 (Wyominga)
1980 1980
519,235 519,235
690,178 (South 690,178 (South ~~Dakot~~aaDakotaa)
393,345 (Montana) 393,345 (Montana)
1970 1970
469,088 469,088
624,181 (North 624,181 (North ~~Dakot~~aaDakotaa) 304,067 ( 304,067 (~~Alask~~aaAl askaa) 1960b)
~~1960b~~
410,481 410,481
484,633 (Maine) 484,633 (Maine)
226,167 ( 226,167 (~~Alask~~aaAl askaa) 1950c)
~~1950c~~
344,587 344,587
395,948 (Rhode Island) 395,948 (Rhode Island)
160,083 ( 160,083 (~~Nevad~~aaN evadaa) 1940c)
~~1940c~~
301,164 301,164
359,231 (Vermon 359,231 (Vermonta)
110,247 ( 110,247 (~~Nevad~~aaN evadaa) 1930c)
~~1930c~~
280,675 280,675
395,982 (New 395,982 (New ~~Mexic~~oaMexicoa)
86,390 ( 86,390 (~~Nevad~~aaNe vadaa) 1920d)
~~1920d~~
— —
— —
— —
~~1910e~~1910e
210,328 210,328
228,027 (Washington) 228,027 (Washington)
80,293 ( 80,293 (~~Nevad~~aaNevadaa)
Source: U.S. Census Bureau, U.S. Census Bureau, Historical ~~Apportionment~~ Apportionment Data (1910-2020), at https://www.census.gov/data/tables/, at https://www.census.gov/data/tables/
time-series/dec/apportionment-data-text.html. time-series/dec/apportionment-data-text.html.
a. State had a single House district during the noted apportionment year. a. State had a single House district during the noted apportionment year.
b. The 1960 apportionment was the first to include b. The 1960 apportionment was the first to include ~~Hawai~~ Hawaii and Alaska,and Alaska, which became states in 1959. which became states in 1959.
c. Apportionments between 1930 and 1950 occurred with 48 states. c. Apportionments between 1930 and 1950 occurred with 48 states.
d. No apportionment occurred after the 1920 Census.d. No apportionment occurred after the 1920 Census.
e. The 1910 apportionment occurred with a House size of 433 and 46 states. Two seats weree. The 1910 apportionment occurred with a House size of 433 and 46 states. Two seats were added to the added to the
House once Arizona and New Mexico became states in 1912. House once Arizona and New Mexico became states in 1912.
To assist states in drawing districts that have equal population sizes, the Census Bureau provides To assist states in drawing districts that have equal population sizes, the Census Bureau provides
population tabulations for certain geographic areas identified by state officials, if requested, under population tabulations for certain geographic areas identified by state officials, if requested, under
the Census Redistricting Data Program, created by P.L. 94-171 in 1975. Under the program, the the Census Redistricting Data Program, created by P.L. 94-171 in 1975. Under the program, the
Census Bureau is required to provide total population counts for Census Bureau is required to provide total population counts for ~~smal~~ small geographic areas; in geographic areas; in
practice, the Bureau also practice, the Bureau also ~~typical y~~typically provides additional demographic information, such as race, provides additional demographic information, such as race,
ethnicity, and voting age population, to states.42 ethnicity, and voting age population, to states.42

~~40 U.S. Census Bureau,~~ 40 U.S. Census Bureau, Historical Apportionment Data (1910-20202), at https://www.census.gov/data/tables/time-, at https://www.census.gov/data/tables/time-
series/dec/apportionmentseries/dec/apportionment -data-text.html. See also Drew-data-text.html. See also Drew Desilver, “Desilver, “ U.S. Population Keeps Growing,U.S. Population Keeps Growing, But House of But House of
Representatives Is SameRepresentatives Is Same ~~Size~~ Size As in As in ~~T aft~~Taft Era,” Era,” FactTank,, Pew Research Center, May 31, 2018, at Pew Research Center, May 31, 2018, at
https://www.pewresearch.org/fact-tank/2018/05/31/u-s-population-keeps-growing-but-house-of-representatives-is-https://www.pewresearch.org/fact-tank/2018/05/31/u-s-population-keeps-growing-but-house-of-representatives-is-
same-size-as-in-taft-era/. same-size-as-in-taft-era/.
41 Adam Mueller, “ 41 Adam Mueller, “~~T he~~The Implications of Legislative Power: State Constitutions, State Legislatures, and Mid-Decade Implications of Legislative Power: State Constitutions, State Legislatures, and Mid-Decade
Redistricting,” Redistricting,” Boston College Law Review, vol. 48 (2007), p. 1351. , vol. 48 (2007), p. 1351.
42 P.L. 94-171, December 23, 1975, 89 Stat. 1023; 13 U.S.C. §141(c). See also U.S.42 P.L. 94-171, December 23, 1975, 89 Stat. 1023; 13 U.S.C. §141(c). See also U.S. ~~Census Bureau, “Redistricting~~
~~Data Program Management,” updated December 27, 2018, at https://www.census.gov/programs-surveys/decennial-~~
~~census/about/rdo/program-management.html; and Catherine McCully,~~ ~~Designing P.L. 94-171 Redistricting Data for~~ Census Bureau, “Redistricting
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Racial/Language Minority Protections43
The Voting Rights Act of 1965 (VRA) also affects how congressional districts are drawn. One key The Voting Rights Act of 1965 (VRA) also affects how congressional districts are drawn. One key
statutory requirement for congressional districts comes from Section 2 of the VRA, as amended, statutory requirement for congressional districts comes from Section 2 of the VRA, as amended,
which prohibits states or their political subdivisions from imposing any voting qualification, which prohibits states or their political subdivisions from imposing any voting qualification,
practice, or procedure that results in denial or abridgement of the right to vote based on race, practice, or procedure that results in denial or abridgement of the right to vote based on race,
color, or membership in a language minority.44 Under the VRA, states cannot draw district maps color, or membership in a language minority.44 Under the VRA, states cannot draw district maps
that have the effect of reducing, or diluting, minority voting strength.45 that have the effect of reducing, or diluting, minority voting strength.45
Other Redistricting Considerations
In addition to requirements of population equality and compliance with the VRA, several other In addition to requirements of population equality and compliance with the VRA, several other
redistricting criteria are common across many states today, including compactness, contiguity, redistricting criteria are common across many states today, including compactness, contiguity,
and observing political boundaries.46 Some of the common redistricting criteria specified by states and observing political boundaries.46 Some of the common redistricting criteria specified by states
are presented iare presented in Table 4. These factors are sometimes referred to as traditional districting These factors are sometimes referred to as traditional districting
principles and are often related to geography. The placement of district boundaries, for example, principles and are often related to geography. The placement of district boundaries, for example,
might reflect natural features of the state’s land; how the population is distributed across a certain might reflect natural features of the state’s land; how the population is distributed across a certain
land area; and efforts to preserve existing subdivisions or communities (such as town boundaries land area; and efforts to preserve existing subdivisions or communities (such as town boundaries
or neighborhood areas). Redistricting laws in many states currently include such criteria, but they or neighborhood areas). Redistricting laws in many states currently include such criteria, but they
are not explicitlyare not explicitly addressed in current federal statute. Previous federal apportionment statutes, addressed in current federal statute. Previous federal apportionment statutes,
however, sometimes contained similar provisions. however, sometimes contained similar provisions.
Table 4. Selected Congressional Redistricting Criteria Specified by Certain States
f
~~s o~~

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ie
s e
s

in
us
ns
iv
io
uo
~~air~~
is
~~unit~~

~~pact~~
al
m
~~petit~~
P
~~bents~~
m
~~ntig~~
~~re”~~
id
~~litic~~
m
m
o
~~tate~~
o
o
o
~~ubdiv~~
o
o
~~reserve~~
vo
S
C
C
P
S
C
~~Interest~~
C
P
“C
A
~~Incum~~
AL
~~Yes~~
~~Yes~~
~~Yes~~
~~Yes~~

Yesau n ities o ts o o nu en act al etitive Pairing e tigu ivisi erve mb mp n re” id litic db mm mp tat u terest vo cu S Co Co Po S Co In Co Pres “Co A In AL Yes Yes Yes Yes Yesa
AZ AZ
Yes Yes
Yes Yes
Yes Yes
Yes Yes
Yes Yes

CA CA
Yes Yes
Yes Yes
Yes Yes
Yes Yes

CO CO
Yes Yes
Yes Yes
Yes Yes
Yes Yes
Yes Yes

FL
~~Yes~~
~~Yes~~
~~Yes~~

GA
~~Yes~~
~~Yes~~
~~Yes~~
~~Yes~~

~~Yesa~~

~~the Year 2020 Census: The View from the States, U.S. Census Bureau,~~ Data Program Management,” updated December 27, 2018, at https://www.census.gov/programs-surveys/decennial-census/about/rdo/program-management.html; and Catherine McCully, Designing P.L. 94-171 Redistricting Data for the Year 2020 Census: The View from the States, U.S. Census Bureau, Washington, DC, December 2014, at Washington, DC, December 2014, at
https://www.census.gov/library/publications/2014/rdo/pl94-171.html.https://www.census.gov/library/publications/2014/rdo/pl94-171.html.
43 43 ~~T his~~This report is not intended to be a legal report is not intended to be a legal analysis of these topics; for additional information on related redistricting analysis of these topics; for additional information on related redistricting
law,law, see CRSsee CRS Legal Sidebar LSB10639, Congressional Redistricting 2021: Legal Framework, CRS Report R44199, Report R44199, Congressional Redistricting: Legal and Constitutional Issues; , and CRSand CRS Report R44798, Report R44798,
Congressional Redistricting Law: Background and Recent Court Rulings. .
44 52 U.S.C.44 52 U.S.C. §§10301, 10303(f)(2). §§10301, 10303(f)(2).
45 52 U.S.C.45 52 U.S.C. §10304; for further discussion,§10304; for further discussion, see CRSsee CRS Report R44798, Report R44798, Congressional Redistricting Law: Background
and Recent Court Rulings, pp. 6-12. , pp. 6-12.
46 An overview of common districting principles, and a chart detailing current requirements across states, are available 46 An overview of common districting principles, and a chart detailing current requirements across states, are available
in National Conference of State Legislatures, “in National Conference of State Legislatures, “ Redistricting Criteria,” Redistricting Criteria,” ~~April 23, 2019~~July 16, 2021, at http://www.ncsl.org/research/, at http://www.ncsl.org/research/
redistricting/redistricting-criteria.aspx. For an overview of how certain criteria have been applied over time, see Micah redistricting/redistricting-criteria.aspx. For an overview of how certain criteria have been applied over time, see Micah
Altman, “Altman, “~~T raditional~~Traditional Districting Principles: Judicial Myths vs. Reality,” Districting Principles: Judicial Myths vs. Reality,” Social Science History,, vol. 22, no. 2 (Summer vol. 22, no. 2 (Summer
1998), pp. 159-200. 1998), pp. 159-200.
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f
~~s o~~

g
ie
s e
s

in
us
ns
iv
io
uo
~~air~~
is
~~unit~~

~~pact~~
al
m
~~petit~~
P
~~bents~~
m
~~ntig~~
~~re”~~
id
~~litic~~
m
m
o
~~tate~~
o
o
o
~~ubdiv~~
o
o
~~reserve~~
vo
S
C
C
P
S
C
~~Interest~~
C
P
“C
A
~~Incum~~
u n ities o ts o o nu en act al etitive Pairing e tigu ivisi erve mb mp n re” id litic db mm mp tat u terest vo cu S Co Co Po S Co In Co Pres “Co A In FL Yes Yes Yes GA Yes Yes Yes Yes Yesa HI HI
Yes Yes
Yes Yes

Yes Yes

ID ID
Yes Yes
Yes Yes
Yes Yes
Yes Yes

IA IA
Yes Yes
Yes Yes
Yes Yes

KS KS
Yes Yes
Yes Yes
Yes Yes
Yes Yes

Yes Yes

KY KY

Yes Yes
Yes Yes
Yes Yes

LA LA

Yes Yes
Yes Yes

Yes Yes

ME ME
Yes Yes
Yes Yes
Yes Yes

MI MI
Yes Yes
Yes Yes
Yes Yes
Yes Yes

Yes Yes

MN MN
Yes Yes
Yes Yes
Yes Yes
Yes Yes

MS MS
Yes Yes
Yes Yes
Yes Yes
Yes Yes

YesaYesa
MO MO
Yes Yes
Yes Yes

MT MT
Yes Yes
Yes Yes
Yes Yes

NE NE
Yes Yes
Yes Yes
Yes Yes

Yes Yes

NV NV
Yes Yes
Yes Yes
Yes Yes

Yes Yes
Yes Yes
NM NM
Yes Yes
Yes Yes
Yes Yes
Yes Yes

~~Yesa~~
YesaY esa Yesa
NY NY
Yes Yes
Yes Yes
Yes Yes
Yes Yes
Yes Yes
Yes Yes

NC NC
Yes Yes
Yes Yes
Yes Yes

YesaYesa
OH OH
Yes Yes
Yes Yes
Yes Yes
Yes Yes

OK OK
Yes Yes
Yes Yes
Yes Yes
Yes Yes

OR
~~Yes~~
Yesa Yesa OR Yes Yes
Yes Yes
Yes Yes

PA PA
Yes Yes
Yes Yes
Yes Yes

RI RI
Yes Yes
Yes Yes
Yes Yes

SC SC
Yes Yes
Yes Yes
Yes Yes
Yes Yes

Yes Yes
Yes Yes
TX

~~Yes~~
~~Yes~~

UT UT
Yes Yes
Yes Yes
Yes Yes
Yes Yes

VA VA
Yes Yes
Yes Yes

Yes Yes

WA WA
Yes Yes
Yes Yes
Yes Yes
Yes Yes
Yes Yes

WV WV
Yes Yes
Yes Yes
Yes Yes

WYb
Yes Yes
Yes Yes
Yes Yes

Source: National Conference of State Legislatures,National Conference of State Legislatures, “Redistricting“Redistricting ~~Systems: A 50-State Overview,” March 29,~~
Criteria,” July 16, 2021, at https://www.ncsl.org/research/2021, at https://www.ncsl.org/research/~~redistrict ing/redist ricting-systems-a-50-state-overview.aspx;~~ redistricting/redistricting-criteria.aspx; and individual and individual
state pages linked fromstate pages linked from ~~Bal otpedia~~ Ballotpedia, “State-by-State Redistricting Procedures,” at https://bal otpedia.org/State-by-, “State-by-State Redistricting Procedures,” at https://bal otpedia.org/State-by-
Congressional Research Service 12 Apportionment and Redistricting Process for the U.S. House of Representatives state_redistricting_procedures.state_redistricting_procedures. Additional information may be available fromAdditional information may be available from individual states. Seeindividual states. See the fol owing the fol owing
text sections for an explanation of the criteriatext sections for an explanation of the criteria used as column headings in this table. used as column headings in this table.
~~Congressional Research Service~~

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~~Apportionment and Redistricting Process for the U.S. House of Representatives~~

Notes: States excluded fromStates excluded from this table do not specify any of these criteria for congressionalthis table do not specify any of these criteria for congressional redistricting.redistricting. These These
states are Alaska,states are Alaska, Arkansas,Arkansas, Connecticut, Delaware,Connecticut, Delaware, Il inois,Il inois, Indiana, Maryland, Massachusetts, New Hampshire, Indiana, Maryland, Massachusetts, New Hampshire,
New Jersey,New Jersey, North Dakota, South Dakota, Tennessee,North Dakota, South Dakota, Tennessee, Texas, Vermont, and Wisconsin.Vermont, and Wisconsin. Some of these states (Alaska, Some of these states (Alaska,
Delaware,Delaware, North Dakota, South Dakota, and Vermont) currently have a single House seat. SomeNorth Dakota, South Dakota, and Vermont) currently have a single House seat. Some states specify states specify
different criteria for state legislativedifferent criteria for state legislative districts. districts.
a. Factor is something that state may “a. Factor is something that state may “~~al ow~~allow” for consideration.” for consideration.
b. State currently only has one congressionalb. State currently only has one congressional district.district.
Compactness and Contiguity
As a districting criterion, compactness reflects the idea that a congressional district should As a districting criterion, compactness reflects the idea that a congressional district should
represent a represent a ~~geographical y~~geographically consolidated area.47 Compactness of congressional districts is a consolidated area.47 Compactness of congressional districts is a
requirement in requirement in 3231 states, but often, state laws do not specify precise measures of compactness.48 states, but often, state laws do not specify precise measures of compactness.48
~~General y~~Generally, a compact district would tend to have smoother boundaries and might resemble a , a compact district would tend to have smoother boundaries and might resemble a
standard geometric shape more than a less compact district. In some conceptualizations, a standard geometric shape more than a less compact district. In some conceptualizations, a
compact district would have an identifiablecompact district would have an identifiable “center” that seems reasonably equidistant from any “center” that seems reasonably equidistant from any
of its boundaries.49 of its boundaries.49
Federal apportionment acts between 1842 and 1911 contained provisions requiring that Federal apportionment acts between 1842 and 1911 contained provisions requiring that
congressional districts be of “contiguous territory,”50 and most states have included similar congressional districts be of “contiguous territory,”50 and most states have included similar
language in their current redistricting laws. For a district to be contiguous, it language in their current redistricting laws. For a district to be contiguous, it ~~general y~~generally must be must be
possible to travel from any point in the district to any other place in the district without crossing possible to travel from any point in the district to any other place in the district without crossing
into a different district.51into a different district.51
Preserving Political Subdivisions
Most states require that redistricting practitioners take into account existing political boundaries, Most states require that redistricting practitioners take into account existing political boundaries,
such as towns, cities, or counties. In many instances, districts may not be able to be drawn in such as towns, cities, or counties. In many instances, districts may not be able to be drawn in
ways that encompass entire political subdivisions, given other districting standards, like ways that encompass entire political subdivisions, given other districting standards, like
population equality, that could take precedence. Maintaining politicalpopulation equality, that could take precedence. Maintaining political subdivisions can also help 47 For additional background ~~subdivisions can also help~~
~~simplify election administration by ensuring that a local election jurisdiction is not split among~~
~~multiple congressional districts. Some state laws direct redistricting authorities to preserve the~~

~~47 For additional background~~ on compactness as a redistricting principle, see William Bunge,on compactness as a redistricting principle, see William Bunge, “Gerrymandering, “Gerrymandering,
Geography, and Grouping,” Geography, and Grouping,” Geographical Review, vol. 56, no. 2 (April 1966), pp. 256-263;, vol. 56, no. 2 (April 1966), pp. 256-263; Jacob S. Siegel, Jacob S. Siegel,
“Geographic Compactness vs. Race/Ethnic Compactness and Other Criteria in the Delineation of Legislative Districts,” “Geographic Compactness vs. Race/Ethnic Compactness and Other Criteria in the Delineation of Legislative Districts,”
Population Research and Policy Review, vol. 15, no. 2 (April 1996), pp. 147, vol. 15, no. 2 (April 1996), pp. 147 -164; Richard G. Niemi et al., “-164; Richard G. Niemi et al., “ Measuring Measuring
Compactness and the Role of a Compactness StandardCompactness and the Role of a Compactness Standard in a in a ~~T est~~Test for Partisan and Racial Gerrymandering,” for Partisan and Racial Gerrymandering,” Journal of
Politics, vol. 52, no. 4 (November 1990), pp. 1155, vol. 52, no. 4 (November 1990), pp. 1155 -1181; and Daniel D. Polsby and Robert D. Popper, “-1181; and Daniel D. Polsby and Robert D. Popper, “ ~~The T hird~~The Third
Criterion: Compactness as a Procedural SafeguardCriterion: Compactness as a Procedural Safeguard Against Partisan Gerrymandering,” Against Partisan Gerrymandering,” Yale Law and Policy Review, ,
vol. 9, no. 2 (Spring/Summervol. 9, no. 2 (Spring/Summer 1991), pp. 3011991), pp. 301 -353. -353.
48 National Conference of State Legislatures, “Redistricting Criteria,” 48 National Conference of State Legislatures, “Redistricting Criteria,” ~~April 23, 2019~~July 16, 2021, at http://www.ncsl.org/research/, at http://www.ncsl.org/research/
redistricting/redistricting-criteria.aspx; for further discussion, see Aaron Kaufman, Garyredistricting/redistricting-criteria.aspx; for further discussion, see Aaron Kaufman, Gary King, and Mayya King, and Mayya
Komisarchik, “How to MeasureKomisarchik, “How to Measure Legislative District Compactness If You Legislative District Compactness If You ~~On ly~~Only Know Know It When You SeeIt When You See It,” working It,” working
paper, updated February 24, 2019, at https://gking.harvard.edu/files/gking/files/compact.pdf, pp. 1-5. paper, updated February 24, 2019, at https://gking.harvard.edu/files/gking/files/compact.pdf, pp. 1-5.
49 See 49 See “Compactness” section from Justin Levitt, “Where Are the Lines Drawn?” “Compactness” section from Justin Levitt, “Where Are the Lines Drawn?” All About Redistricting, Loyola Law , Loyola Law
School, 2020, at http://redistricting.lls.edu/where-state.php#contiguity. School, 2020, at http://redistricting.lls.edu/where-state.php#contiguity.
50 Historical apportionment acts can be viewed50 Historical apportionment acts can be viewed at U.S.at U.S. ~~Census~~ Census Bureau,Bureau, “Apportionment Legislation 1840“Apportionment Legislation 1840 -1880,” -1880,”
History, at https://www.census.gov/history/www/reference/apportionment/apportionment_legislation_1840_-, at https://www.census.gov/history/www/reference/apportionment/apportionment_legislation_1840_-
_1880.html; U.S. Census_1880.html; U.S. Census Bureau,Bureau, “ “Apportionment Legislation 1890Apportionment Legislation 1890 -Present,” -Present,” History, at https://www.census.gov/, at https://www.census.gov/
history/www/reference/apportionment/apportionment_legislation_1890_-_present.html. history/www/reference/apportionment/apportionment_legislation_1890_-_present.html.
51 See 51 See “Contiguity” section from Justin Levitt, “Where Are the Lines Drawn?” “Contiguity” section from Justin Levitt, “Where Are the Lines Drawn?” All About Redistricting, Loyola Law , Loyola Law
School, 2020, at https://redistricting.lls.edu/redistricting-101/where-are-the-lines-drawn/#contiguity. School, 2020, at https://redistricting.lls.edu/redistricting-101/where-are-the-lines-drawn/#contiguity.
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simplify election administration by ensuring that a local election jurisdiction is not split among multiple congressional districts. Some state laws direct redistricting authorities to preserve the “core” of existing congressional districts; other states prohibit drawing district boundaries that “core” of existing congressional districts; other states prohibit drawing district boundaries that
would create electoral contests between incumbent House Members.52would create electoral contests between incumbent House Members.52
Preserving Communities of Interest
Some states include the preservation of communities of interest as a criterion in their redistricting Some states include the preservation of communities of interest as a criterion in their redistricting
laws. People within a community of interest laws. People within a community of interest ~~general y~~generally have a shared background or common have a shared background or common
interests that may be relevant to their legislativeinterests that may be relevant to their legislative representation. These representation. These ~~rec ognized~~recognized similarities similarities
may be due to shared social, cultural, historical, racial, ethnic, partisan, or economic factors. In may be due to shared social, cultural, historical, racial, ethnic, partisan, or economic factors. In
some instances, communities of interest may some instances, communities of interest may ~~natural y~~naturally be preserved by following other be preserved by following other
redistricting criteria, such as compactness or preserving political subdivisions.53redistricting criteria, such as compactness or preserving political subdivisions.53
Promoting Political Competition; Considering Existing District or Incumbent
Some states include measures providing that districts cannot be drawn to unduly favor a particular Some states include measures providing that districts cannot be drawn to unduly favor a particular
candidate or politicalcandidate or political party. The term party. The term gerrymander originated to describe districts drawn to favor originated to describe districts drawn to favor
a particular political party,54 and it is often used in this context today. Redistricting has a particular political party,54 and it is often used in this context today. Redistricting has
~~traditional y~~ traditionally been viewed as an inherently political process, where authorities have used partisan been viewed as an inherently political process, where authorities have used partisan
considerations in drawing district boundaries. Districts considerations in drawing district boundaries. Districts ~~general y~~generally may be drawn in a way that is may be drawn in a way that is
~~political y~~ politically advantageous to certain candidates or political parties, unless prohibited by state law.55 advantageous to certain candidates or political parties, unless prohibited by state law.55
Some states, for example, expressly Some states, for example, expressly ~~al ow~~allow the use of party identification information in the the use of party identification information in the
redistricting process, whereas others prohibit it; similarly, some states may redistricting process, whereas others prohibit it; similarly, some states may ~~al ow~~allow for practices to for practices to
protect an incumbent or maintain the “core” of an existing district, whereas other states prohibit protect an incumbent or maintain the “core” of an existing district, whereas other states prohibit
any practices that would favor or disfavor an incumbent or candidate.56 any practices that would favor or disfavor an incumbent or candidate.56
State Processes for Redistricting
Redistricting processes are Redistricting processes are ~~fundamental y~~fundamentally the responsibility of state governments under current the responsibility of state governments under current
law and practice. Among the 44 states with multiple House districts, a variety of approaches are law and practice. Among the 44 states with multiple House districts, a variety of approaches are
taken, but taken, but ~~general y~~generally, states either , states either ~~al ow~~allow their state legislatures or a separate redistricting their state legislatures or a separate redistricting
commission to determine congressional district boundaries. The map icommission to determine congressional district boundaries. The map in Figure 3 displays the displays the
redistricting methods currently used across states. redistricting methods currently used across states.

52 National Conference of State Legislatures, “Redistricting Criteria,” 52 National Conference of State Legislatures, “Redistricting Criteria,” ~~April 23, 2019~~July 16, 2021, at http://www.ncsl.org/research/, at http://www.ncsl.org/research/
redistricting/redistricting-criteria.aspx. redistricting/redistricting-criteria.aspx.
53 See 53 See “Communities of interest” section from Justin Levitt, “Where Are the Lines Drawn?” “Communities of interest” section from Justin Levitt, “Where Are the Lines Drawn?” All About Redistricting, ,
Loyola Law School, 2020, at https://redistricting.lls.edu/redistricting-101/where-are-the-lines-drawn/Loyola Law School, 2020, at https://redistricting.lls.edu/redistricting-101/where-are-the-lines-drawn/
#communities+of+interest#communities+of+interest . .
54 In 1812, the term was coined to describe54 In 1812, the term was coined to describe a salamander-shaped state legislative district in Massachusetts that a salamander-shaped state legislative district in Massachusetts that
benefitted Governor Elbridgebenefitted Governor Elbridge Gerry’s party. See Erick Gerry’s party. See Erick ~~T rickey~~Trickey, “Where Did the , “Where Did the ~~T erm~~Term ‘Gerrymander’ ‘Gerrymander’ ~~Com e~~Come From?” From?”
~~Sm ithsonian~~Smithsonian Magazine, July 20, 2017, at https://www.smithsonianmag.com/history/where-did-term-gerrymander-, July 20, 2017, at https://www.smithsonianmag.com/history/where-did-term-gerrymander-
come-180964118/. come-180964118/.
55 Cases 55 Cases ~~addressing~~ addressing partisan gerrymandering have recently been heard by the Supreme Court; for more information, see partisan gerrymandering have recently been heard by the Supreme Court; for more information, see
CRSCRS Legal SidebarLegal Sidebar LSB10324, LSB10324, Partisan ~~Gerrym andering Claim s~~Gerrymandering Claims Not Subject to Federal Court Review:
Considerations Going Forward; CRS; CRS Legal SidebarLegal Sidebar LSB10276, LSB10276, ~~Suprem e~~Supreme Court Once Again Considers Partisan
~~Gerrym andering: Im plications~~Gerrymandering: Implications and Legislative Options; and CRS; and CRS Legal SidebarLegal Sidebar LSB10164, LSB10164, Partisan ~~Gerrym andering:~~
~~Suprem e~~Gerrymandering: Supreme Court Provides Guidance on Standing and Maintains Legal Status Quo . .
56 National Conference of State Legislatures, “Redistricting Criteria,” 56 National Conference of State Legislatures, “Redistricting Criteria,” ~~April 23, 2019~~July 16, 2021, at http://www.ncsl.org/research/, at http://www.ncsl.org/research/
redistricting/redistricting-criteria.aspx. redistricting/redistricting-criteria.aspx.
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Figure 3. State Redistricting Methods

Source: CRS compilation, CRS compilation, based on information frombased on information from ~~Bal otpedia~~ Ballotpedia and the National Conference of State and the National Conference of State
Legislatures.Legislatures. Graphic created by Amber Hope Wilhelm,Graphic created by Amber Hope Wilhelm, CRS Visual Information Specialist. CRS Visual Information Specialist.
Notes: Iowa has nonpartisan legislative Iowa has nonpartisan legislative staff create its redistrictingstaff create its redistricting maps but requiresmaps but requires ~~legislative~~ legislative approval to approval to
enact them. In New York, redistrictingenact them. In New York, redistricting plans also require gubernatorial approval. plans also require gubernatorial approval.
~~Historical y~~Historically, and in the majority of states today, congressional district boundaries are primarily , and in the majority of states today, congressional district boundaries are primarily
determined by state legislatures. Currently, determined by state legislatures. Currently, 3633 states authorize their state legislatures to establish states authorize their state legislatures to establish
congressional district boundaries. Most of these states enable the governor to veto a redistricting congressional district boundaries. Most of these states enable the governor to veto a redistricting
plan created by the legislature; Connecticut and North Carolina do not plan created by the legislature; Connecticut and North Carolina do not ~~al ow~~allow a gubernatorial a gubernatorial
veto.57 veto.57
In recent years, other states have begun to use redistricting commissions, which may be more In recent years, other states have begun to use redistricting commissions, which may be more
removed from state legislative politics.58 In removed from state legislative politics.58 In 1011 states that currently have multiple congressional states that currently have multiple congressional
districts (Arizona, California, Colorado, districts (Arizona, California, Colorado, ~~Hawai~~ Hawaii, Idaho, Michigan, Montana, New Jersey, , Idaho, Michigan, Montana, New Jersey,
New York, Virginia,Virginia, and Washington), redistricting commissions are primarily responsible for redrawing and Washington), redistricting commissions are primarily responsible for redrawing
congressional districts. In congressional districts. In ~~four~~three other states (Maine, other states (Maine, ~~New York,~~ Rhode Island, and Utah), a Rhode Island, and Utah), a
commission serves in an advisory capacity during the redistricting process. Commissions may commission serves in an advisory capacity during the redistricting process. Commissions may
also be used as a “backup” or alternate means of redistricting if the legislature’s plan is not also be used as a “backup” or alternate means of redistricting if the legislature’s plan is not
enacted, such as in Connecticut, Indiana, and Ohio. enacted, such as in Connecticut, Indiana, and Ohio.
The composition of congressional redistricting commissions can also vary; many include The composition of congressional redistricting commissions can also vary; many include
members of the public selected by a method intended to be nonpartisan or bipartisan, whereas members of the public selected by a method intended to be nonpartisan or bipartisan, whereas
other commissions may include political appointees or elected officials, such as in other commissions may include political appointees or elected officials, such as in ~~Hawai~~ Hawaii and and
New Jersey. A commission’s membership, the authority granted to it, its relationship to other state New Jersey. A commission’s membership, the authority granted to it, its relationship to other state
government entities, and other features may affect whether a commission is perceived to be government entities, and other features may affect whether a commission is perceived to be
undertaking an objective process or a more politicized one. Some proponents of redistricting undertaking an objective process or a more politicized one. Some proponents of redistricting
commissions believe that using independent redistricting commissions can prevent opportunities commissions believe that using independent redistricting commissions can prevent opportunities

~~57 See~~ 57 See “State-by-State Redistricting Procedures,” “State-by-State Redistricting Procedures,” Ballotpedia, at https://ballotpedia.org//State-by-, at https://ballotpedia.org//State-by-
state_redistricting_procedures. state_redistricting_procedures.
58 58 ~~Wendy Underhill~~National Conference of State Legislatures, “Redistricting Commissions: Congressional Plans,” , “Redistricting Commissions: Congressional Plans,” ~~National Conference of State Legislatures,~~
~~April 18, 2019~~July 12, 2021, at http://www.ncsl.org/research/redistricting/redistricting-commissions-congressional-plans.aspx. , at http://www.ncsl.org/research/redistricting/redistricting-commissions-congressional-plans.aspx.
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for partisan gerrymandering and may create more competitive and representative districts.59 for partisan gerrymandering and may create more competitive and representative districts.59
Others, however, believe that political considerations can remain in commission decisionmaking Others, however, believe that political considerations can remain in commission decisionmaking
processes, and that the effect of redistricting methods on electoral competitiveness is overstated.60 processes, and that the effect of redistricting methods on electoral competitiveness is overstated.60
For more information on redistricting commissions, see CRS Insight IN11053, For more information on redistricting commissions, see CRS Insight IN11053, Redistricting
Commissions for Congressional Districts. .
The timeline for redistricting also varies across states, and can be affected by state or federal The timeline for redistricting also varies across states, and can be affected by state or federal
requirements regarding the redistricting process; the efficiency of the legislature, commission, or requirements regarding the redistricting process; the efficiency of the legislature, commission, or
other entities involved in drawing a state’s districts; and, other entities involved in drawing a state’s districts; and, ~~potential y~~potentially, by legal or political , by legal or political
~~chal enges~~challenges made to a drafted or enacted redistricting plan.61 In general, the redistricting process made to a drafted or enacted redistricting plan.61 In general, the redistricting process
would would ~~usual y~~usually begin early in a year ending in “1,” once each state has learned how many seats it begin early in a year ending in “1,” once each state has learned how many seats it
is entitled to under the apportionment following the decennial census.62 Many states complete the is entitled to under the apportionment following the decennial census.62 Many states complete the
process within the next year. After the 2010 reapportionment, for example, Iowa was the first process within the next year. After the 2010 reapportionment, for example, Iowa was the first
state to complete its initialstate to complete its initial congressional redistricting plan on March 31, 2011, and 31 other states congressional redistricting plan on March 31, 2011, and 31 other states
completed their initialcompleted their initial plans by the end of 2011. The remaining 11 states with multiple plans by the end of 2011. The remaining 11 states with multiple
congressional districts completed their initial redistricting plans by the middle of 2012, with congressional districts completed their initial redistricting plans by the middle of 2012, with
Kansas becoming the final state to complete its initialKansas becoming the final state to complete its initial plan on June 7, 2012.63 Some states may plan on June 7, 2012.63 Some states may
~~redistrict multiple times between apportionments, if al owed under state law or required by a legal~~
~~chal enge to the preliminary redistricting.64~~

59 Katie Zezima and Emily Wax-59 Katie Zezima and Emily Wax-~~T hibodeaux~~Thibodeaux, “Voters Are Stripping Partisan Redistricting Power from Politicians in , “Voters Are Stripping Partisan Redistricting Power from Politicians in
Anti-Gerrymandering Efforts,” Anti-Gerrymandering Efforts,” Washington Post, November 7, 2018, at https://www.washingtonpost.com/national/, November 7, 2018, at https://www.washingtonpost.com/national/
voters-are-stripping-partisan-redistricting-power-from-politicians-in-anti-gerrymandering-efforts/2018/11/07/voters-are-stripping-partisan-redistricting-power-from-politicians-in-anti-gerrymandering-efforts/2018/11/07/
2a239a5e-e1d9-11e8-b759-3d88a5ce9e19_story.html; Lyle Denniston, “2a239a5e-e1d9-11e8-b759-3d88a5ce9e19_story.html; Lyle Denniston, “ Opinion Analysis: A CureOpinion Analysis: A Cure for Partisan for Partisan
Gerrymandering?” Gerrymandering?” SCOTUSblog, June 29, 2015, at https://www.scotusblog.com/2015/06/opinion-analysis-a-cure-for-, June 29, 2015, at https://www.scotusblog.com/2015/06/opinion-analysis-a-cure-for-
partisan-gerrymandering/. partisan-gerrymandering/.
60 For example, see Alan Abramowitz, Brad Alexander, and Matthew Gunning,60 For example, see Alan Abramowitz, Brad Alexander, and Matthew Gunning, “Don't Blame Redistricting for “Don't Blame Redistricting for
Uncompetitive Elections,” Uncompetitive Elections,” PS: Political Science and Politics, vol. 2839, no. 1 (January 2006), pp. 87-90, vol. 2839, no. 1 (January 2006), pp. 87-90.
~~61 For general historical background~~ ; David A. Lieb, “New redistricting commissions splinter along partisan lines,” AP News, September 18, 2021, at https://apnews.com/article/elections-ohio-virginia-redistricting-voting-districts-b27ebd5a7dd99ad613ac896ed16ffcde; Meagan Flynn, “Virginia’s redistricting commission’s failure to transcend partisanship has lessons for other states, critics say,” Washington Post, October 25, 2021, at https://www.washingtonpost.com/dc-md-va/2021/10/25/redistricting-virginia-lessons-partisan/; and Nick Corasaniti and Reid J. Epstein, “How a Cure for Gerrymandering Left U.S. Politics Ailing in New Ways,” New York Times, November 17, 2021, at https://www.nytimes.com/2021/11/17/us/politics/gerrymandering-redistricting.html. 61 For general historical background and an analysis of state redistricting timeline considerations, see Erik J. Engstrom, and an analysis of state redistricting timeline considerations, see Erik J. Engstrom,
““~~T he Strategic T iming~~The Strategic Timing of Congressional Redistricting,” ch. 4 in of Congressional Redistricting,” ch. 4 in Partisan Gerrymandering and the Construction of
~~Am erican Dem ocracy~~American Democracy (Ann Arbor, MI: University of Michigan Press, 2013), pp. 59 (Ann Arbor, MI: University of Michigan Press, 2013), pp. 59 -79. A number of lawsuits-79. A number of lawsuits related to related to
redistricting followingredistricting following the 2010 census remain pendingthe 2010 census remain pending in 2019; see David A. Lieb, “Gerrymandering Lawsuitsin 2019; see David A. Lieb, “Gerrymandering Lawsuits Are Are
Pending in a Dozen Pending in a Dozen ~~St ates~~States,” Associated Press, March 21, 2019, at https://apnews.com//,” Associated Press, March 21, 2019, at https://apnews.com//
0e7691a32c954975850de9e78b9b73cc. According to one count, lawsuits were0e7691a32c954975850de9e78b9b73cc. According to one count, lawsuits were ~~filed~~ filed in 38 states duringin 38 states during the 2010 the 2010
redistricting cycle; see “redistricting cycle; see “ Redistricting LawsuitsRedistricting Lawsuits ~~Related~~ Related to the 2010 Census,” to the 2010 Census,” Ballotpedia, updated April 17, 2019, at , updated April 17, 2019, at
https://ballotpedia.org//https://ballotpedia.org//~~Redistricting_lawsuits_relating_t o_the_2010_Census.~~
~~62 T he Census Bureau~~ Redistricting_lawsuits_relating_to_the_2010_Census. 62 The Census Bureau announced that states will beannounced that states will be receiving redistricting data basedreceiving redistricting data based on the 2020 census by September on the 2020 census by September
30, 2021. See James Whitehorne, “Timeline for Releasing Redistricting Data,” 30, 2021. See James Whitehorne, “Timeline for Releasing Redistricting Data,” U.S. Census Bureau, February 12, 2021, , February 12, 2021,
at https://www.census.gov/newsroom/blogs/random-samplings/2021/02/timeline-redistricting-data.html. at https://www.census.gov/newsroom/blogs/random-samplings/2021/02/timeline-redistricting-data.html.
63 Catherine McCully, “ 63 Catherine McCully, “~~T able~~Table 3. Redistricting 3. Redistricting ~~T imelines~~Timelines—Data Delivery and Initial Plan Passage” in —Data Delivery and Initial Plan Passage” in Designing P.L.
94-171 Redistricting Data for the Year 2020 Census: The View ~~from~~ from the States, U.S., U.S. ~~Census~~ Census Bureau,Bureau, Washington, DC, Washington, DC,
December 2014, p. 26, at https://www.census.gov/library/publications/2014/rdo/pl94-171.html. For an illustration of December 2014, p. 26, at https://www.census.gov/library/publications/2014/rdo/pl94-171.html. For an illustration of
the timeline of how redistricting processes unfoldedthe timeline of how redistricting processes unfolded across states followingacross states following the 2010 apportionment, see the chart the 2010 apportionment, see the chart
created by Justin Levitt, “Maps across the 2010 cycle,” created by Justin Levitt, “Maps across the 2010 cycle,” All About Redistricting, Loyola Law, Loyola Law School, 2020, at School, 2020, at
https://redistricting.lls.edu/resources/maps-across-the-cycle-2010-congress/. District maps may also face later legal https://redistricting.lls.edu/resources/maps-across-the-cycle-2010-congress/. District maps may also face later legal
challenges that require further adjustments; see Michael Li, challenges that require further adjustments; see Michael Li, ~~T homas~~Thomas Wolf, Wolf, and Annie Lo, “and Annie Lo, “ ~~T he~~The State of Redistricting State of Redistricting
Litigation,” Brennan Center for Justice, April 1, 2021, at https://www.brennancenter.org/blog/state-redistricting-Litigation,” Brennan Center for Justice, April 1, 2021, at https://www.brennancenter.org/blog/state-redistricting-
litigation for a list of ongoing litigation for congressional and state legislative districts. litigation for a list of ongoing litigation for congressional and state legislative districts.
~~64 Justin Levitt and Michael P. McDonald, “T aking the ‘Re’ out of Redistricting: State Constitutional Provisions on~~
~~Redistricting T iming,” Georgetown Law Journal, vol. 95 (2007), pp. 1247-1285; Adam Mueller, “T he Implications of~~
~~Legislative Power: State Constitutions, State Legislatures, and Mid-Decade Redistricting,”~~ ~~Boston College Law~~
~~Review, vol. 48 (2007), pp. 1343-1386.~~
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Congressional Research Service 16 Apportionment and Redistricting Process for the U.S. House of Representatives redistrict multiple times between apportionments, if allowed under state law or required by a legal challenge to the preliminary redistricting.64
Congressional Options Regarding Redistricting
Although redistricting processes in practice today are largely governed by state law, Congress Although redistricting processes in practice today are largely governed by state law, Congress
has, at times, considered an expanded federal government role, which could serve to standardize has, at times, considered an expanded federal government role, which could serve to standardize
certain elements of the redistricting process across states. Given the certain elements of the redistricting process across states. Given the ~~historical y~~historically limited role the limited role the
federal government has played in the redistricting process, concerns about federalism may arise in federal government has played in the redistricting process, concerns about federalism may arise in
the context of certain congressional efforts addressing redistricting. The types of legislative the context of certain congressional efforts addressing redistricting. The types of legislative
proposals briefly introduced in this section reflect some common examples of redistricting proposals briefly introduced in this section reflect some common examples of redistricting ~~bil s~~
bills introduced in recent Congresses; they are not meant to be an exhaustive list of introduced in recent Congresses; they are not meant to be an exhaustive list of al all the options the options
Congress has considered or could consider related to redistricting. Congress has considered or could consider related to redistricting.
Some legislative Some legislative proposals in recent Congresses would establish criteria for districts, such as proposals in recent Congresses would establish criteria for districts, such as
population equality, compactness, contiguity, or preservation of existing political subdivisions.65 population equality, compactness, contiguity, or preservation of existing political subdivisions.65
~~Bil s~~ Bills have also been introduced that would require states to use independent redistricting have also been introduced that would require states to use independent redistricting
commissions and/or maintain certain standards of public input and transparency regarding the commissions and/or maintain certain standards of public input and transparency regarding the
redistricting process.66 Some congressional redistricting process.66 Some congressional ~~bil s~~bills include provisions to prevent states from include provisions to prevent states from
redistricting more than once following an apportionment, which is a practice sometimes referred redistricting more than once following an apportionment, which is a practice sometimes referred
to as “mid-decade redistricting.”67 Other to as “mid-decade redistricting.”67 Other ~~bil s~~bills would expand oversight by the Department of would expand oversight by the Department of
Justice under certain circumstances related to existing requirements of, or proposed amendments Justice under certain circumstances related to existing requirements of, or proposed amendments
~~to, the VRA.68~~
~~Most of these bil s have been referred to committee but not passed by either chamber. In the 117th~~
~~Congress, the House passed H.R. 1, and a similar version of H.R. 1 was also passed by the House~~
~~in the 116th Congress. H.R. 1 is a multifaceted bil that addresses multiple areas of election~~
~~administration, among other topics; with respect to redistricting, it would require states to use~~
~~independent redistricting commissions, adopt certain redistricting criteria, and prohibit mid-~~
~~decade redistricting.69~~
~~Concluding Observations~~
~~Apportionment and redistricting address fundamental elements of representational democracy.~~
~~Determining how many elected representatives should serve in the House, and how many people~~
~~should be in each congressional district, are central questions for those who are concerned with~~
~~how responsive the House can be to the interests of the American public. During earlier eras in~~

~~65 Such bills from the 117th Congress to date include H.R. 1, S. 1, and H.R. 80. Such bills~~ to, the VRA.68 64 Justin Levitt and Michael P. McDonald, “Taking the ‘Re’ out of Redistricting: State Constitutional Provisions on Redistricting Timing,” Georgetown Law Journal, vol. 95 (2007), pp. 1247-1285; Adam Mueller, “The Implications of Legislative Power: State Constitutions, State Legislatures, and Mid-Decade Redistricting,” Boston College Law Review, vol. 48 (2007), pp. 1343-1386. 65 Such bills from the 117th Congress to date include H.R. 1, S. 1, H.R. 80, H.R. 3863, H.R. 4307, S. 2093, S. 2670, and S. 2747. Such bills from the 116th Congress included ~~from the 116th Congress~~
~~included~~ H.R. 1, H.R. 124, H.R. 130, H.R. 1612, H.R. 3572, H.R. 4000, S. 949, S.H.R. 1, H.R. 124, H.R. 130, H.R. 1612, H.R. 3572, H.R. 4000, S. 949, S. 1972, and S.1972, and S. 2226. Such bills2226. Such bills from from
the 115th Congress includedthe 115th Congress included H.R. 711, H.R. 712, H.R. 1102, H.R. 3537, H.R. 3848, S. 1880, and S.H.R. 711, H.R. 712, H.R. 1102, H.R. 3537, H.R. 3848, S. 1880, and S. 3123. 3123.
66 Bills 66 Bills from the 117th Congress to date that wouldfrom the 117th Congress to date that would ~~require~~ require states to use redistricting commissions includestates to use redistricting commissions include H.R. 1, S.H.R. 1, S. 1, 1,
H.R. 80, H.R. 80, ~~and H.R. 100. Bills~~ H.R. 100, H.R. 3863, H.R. 4307, S. 2093, and S. 2670. Bills from the 116th Congress that wouldfrom the 116th Congress that would have requiredhave required states to use redistricting commissions states to use redistricting commissions
~~included~~ included H.R. 1, H.R. 124, H.R. 130, H.R. 163, H.R. H.R. 1, H.R. 124, H.R. 130, H.R. 163, H.R. ~~160, H.R.~~ 1612, H.R. 3572, H.R. 4000, S. 949, and S.1612, H.R. 3572, H.R. 4000, S. 949, and S. 2226; bills 2226; bills
from the 115th Congress that wouldfrom the 115th Congress that would have requiredhave required states to usestates to use redistricting commissions includedredistricting commissions included H.R. 145, H.R. 711, H.R. 145, H.R. 711,
H.R. 712, H.R. 1102, H.R. 2981, H.R. 3537, H.R. 3848, and S.H.R. 712, H.R. 1102, H.R. 2981, H.R. 3537, H.R. 3848, and S. 1880. Another proposal from the 117th Congress, S. 2747, would not create this requirement for states but would provide funding to states that engage in certain election practices, including using an independent redistricting commission. ~~1880.~~ Some billsSome bills related to redistricting commissions related to redistricting commissions
have also includedhave also included measures to provide for publicmeasures to provide for public input and transparency regarding the redistricting process. Other bills input and transparency regarding the redistricting process. Other bills
have includedhave included provisions to include publicprovisions to include public participation in redistricting processesparticipation in redistricting processes or public notice about district boundary changes, but would ~~, but would~~ not require states to use not require states to use
redistricting commissions. redistricting commissions. ~~T hese bills include H.R. 81 and~~ Bills addressing public participation in redistricting include H.R. 81 and H.R. 1366 in the 117th Congress to date; similarH.R. 1366 in the 117th Congress to date; similar measures measures
from previous Congressesfrom previous Congresses ~~included~~ included H.R. 131 and H.R. 1799 in the 116th Congress, and H.R. H.R. 131 and H.R. 1799 in the 116th Congress, and H.R. 713 in the 115th Congress. Bills introduced in the 117th Congress addressing public notice about district boundary changes under certain circumstances include H.R. 4, H.R. 1366, and S. 4; similar measures from previous Congresses included H.R. 4, H.R. 1799, H.R. 8053, H.R. 8352, S. 561, and S. 4263 from the 116th Congress; and H.R. 2978, H.R. 3239, H.R. 5785 and S. 1419 from the 115th Congress. 67 Such bills ~~713 in the 115th Congress.~~
~~67 Such bills~~ from the 117th Congress to date includefrom the 117th Congress to date include ~~H.R. 1, S. 1, and H.R. 134. Such bills~~ H.R. 1, H.R. 80, H.R. 134, H.R. 4307 S. 1, S. 2093, S. 2670, and S. 2747. Such bills from the 116th Congress from the 116th Congress
~~included~~ included H.R. 1, H.R. 44, H.R. 124, H.R. 130, H.R. 1612, H.R. 3572, H.R. 4000, S. 949, S.H.R. 1, H.R. 44, H.R. 124, H.R. 130, H.R. 1612, H.R. 3572, H.R. 4000, S. 949, S. 1972, and S.1972, and S. 2226; such 2226; such
~~bills~~ bills from the 115th Congress includedfrom the 115th Congress included H.R. 711, H.R. 712, H.R. 1102, H.R. 3537, H.R. 3848, and S.H.R. 711, H.R. 712, H.R. 1102, H.R. 3537, H.R. 3848, and S. 1880. 1880.
68 Examples of such 68 Examples of such ~~bills include H.R. 4 and S. 561~~ bills from the 117th Congress include H.R. 4 and S. 4; examples from the 116th Congress from the 116th Congress ~~and H.R. 151, H.R. 3239, and S. 1419~~
~~from the 115th Congress.~~
~~69 For additional information and resources, see CRS In Focus IF11097, H.R. 1: Overview and Related CRS Products.~~
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~~the United States, the number of seats in the House of Representatives general y~~include Congressional Research Service 17 Apportionment and Redistricting Process for the U.S. House of Representatives Most of these bills have been referred to committee but not passed by either chamber. In the 117th Congress, the House passed H.R. 1, and a similar version of H.R. 1 was also passed by the House in the 116th Congress. H.R. 1 is a multifaceted bill that addresses multiple areas of election administration, among other topics; with respect to redistricting, it would require states to use independent redistricting commissions, adopt certain redistricting criteria, and prohibit mid-decade redistricting.69 Concluding Observations Apportionment and redistricting address fundamental elements of representational democracy. Determining how many elected representatives should serve in the House, and how many people should be in each congressional district, are central questions for those who are concerned with how responsive the House can be to the interests of the American public. During earlier eras in the United States, the number of seats in the House of Representatives generally increased as the increased as the
American population increased, and district sizes could be kept more equal over time and across American population increased, and district sizes could be kept more equal over time and across
states. The House size, however, has been set at 435 seats throughout the last century, while the states. The House size, however, has been set at 435 seats throughout the last century, while the
national population has continued to grow and concentrate in certain geographic areas, leading to national population has continued to grow and concentrate in certain geographic areas, leading to
larger constituencies across larger constituencies across al all House districts over time and disparate district sizes across states. House districts over time and disparate district sizes across states.
Certain elements of the apportionment process are established by the U.S. Constitution. This Certain elements of the apportionment process are established by the U.S. Constitution. This
includes the requirement for representation in the House based on state population size; the includes the requirement for representation in the House based on state population size; the
~~real ocation~~reallocation of House seats every 10 years upon the completion of a national population count; of House seats every 10 years upon the completion of a national population count;
and the requirements that each state receives at least one Representative and that there can be no and the requirements that each state receives at least one Representative and that there can be no
more than one Representative for every 30,000 persons. Other elements of the process are more than one Representative for every 30,000 persons. Other elements of the process are
addressed through federal legislation, such as the addressed through federal legislation, such as the ~~overal~~ overall number of House seats or method of number of House seats or method of
distributing seats among the states. Congress more regularly legislated in this area prior to the distributing seats among the states. Congress more regularly legislated in this area prior to the
mid-20th century, passing decennial acts to address upcoming censuses and apportionments, rather mid-20th century, passing decennial acts to address upcoming censuses and apportionments, rather
than creating than creating ~~bil s~~bills intended to apply for intended to apply for al all future reapportionment cycles. future reapportionment cycles.
Whereas apportionment is a process largely governed by federal statute, redistricting is a process, Whereas apportionment is a process largely governed by federal statute, redistricting is a process,
in practice, largely governed by state law. Certain federal standards apply to House districts, in practice, largely governed by state law. Certain federal standards apply to House districts,
~~general y~~generally in the interest of preserving equal access to representation, but the method and timeline in the interest of preserving equal access to representation, but the method and timeline
by which those districts are created is largely determined by state law. In states with multiple by which those districts are created is largely determined by state law. In states with multiple
congressional districts, there are a multitude of ways in which district boundaries can be drawn, congressional districts, there are a multitude of ways in which district boundaries can be drawn,
depending upon the criteria used to create the districts. There is often an expectation that depending upon the criteria used to create the districts. There is often an expectation that
congressional districts congressional districts ~~wil~~ will be drawn in a way that ensures “fair” representation, but “fairness” be drawn in a way that ensures “fair” representation, but “fairness”
can be a somewhat subjective determination. can be a somewhat subjective determination.
Many lawmakers and members of the public may agree on some of the more basic Many lawmakers and members of the public may agree on some of the more basic
representational principles embedded in apportionment and redistricting law, but can find it representational principles embedded in apportionment and redistricting law, but can find it
difficult to apply those principles in practice. The criteria commonly used for redistricting today difficult to apply those principles in practice. The criteria commonly used for redistricting today
reflect a combination of state and federal statutes, judicial interpretations, and practices from past reflect a combination of state and federal statutes, judicial interpretations, and practices from past
redistricting cycles that may require trade-offs between one consideration and another. Ensuring redistricting cycles that may require trade-offs between one consideration and another. Ensuring
equal population size across equal population size across al all congressional districts, for example, may be an agreeable goal for congressional districts, for example, may be an agreeable goal for
many individuals. In practice, however, the geographic and demographic distribution of residents many individuals. In practice, however, the geographic and demographic distribution of residents
within and across states, coupled with requirements to observe state boundaries, provide within and across states, coupled with requirements to observe state boundaries, provide ~~al states~~all states H.R. 4, H.R. 1799, H.R. 8352, S. 561, and S. 4263; and H.R. 151, H.R. 2978, H.R. 3239, H.R. 5785, and S. 1419 from the 115th Congress. 69 For additional information and resources, see CRS In Focus IF11097, H.R. 1 and S. 1: Overview and Related CRS Products. Congressional Research Service 18 Apportionment and Redistricting Process for the U.S. House of Representatives
with at least one Representative, and maintain a constant number of House seats, make this goal with at least one Representative, and maintain a constant number of House seats, make this goal
more difficult to achieve. Although mapmaking software today can design districts with more difficult to achieve. Although mapmaking software today can design districts with
increasing precision with respect to geographic boundaries and population characteristics, this increasing precision with respect to geographic boundaries and population characteristics, this
technological capacity has not necessarily simplified the technological capacity has not necessarily simplified the ~~overal~~ overall task of redistricting. A majority task of redistricting. A majority
of states faced legal of states faced legal ~~chal enges~~challenges to congressional district maps drawn following the 2010 census, to congressional district maps drawn following the 2010 census,
reflecting differing perspectives on fairness, representational access, and how competing reflecting differing perspectives on fairness, representational access, and how competing
redistricting criteria should be weighted. redistricting criteria should be weighted.
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Appendix. Determining an Apportionment Method
Congress is a bicameral legislature, in which each state receives equal representation in the Congress is a bicameral legislature, in which each state receives equal representation in the
Senate and each state’s representation in the House is based upon its population. Senate and each state’s representation in the House is based upon its population. ~~Essential y~~Essentially, any , any
method of apportionment for the House must consider three key variables: (1) the number of method of apportionment for the House must consider three key variables: (1) the number of
House seats; (2) the number of U.S. states; and (3) the apportionment population of each state. A House seats; (2) the number of U.S. states; and (3) the apportionment population of each state. A
mathematical decision must also be made regarding how fractions of seats are addressed, since mathematical decision must also be made regarding how fractions of seats are addressed, since
House seats must be House seats must be ~~al ocated~~allocated as whole numbers, and simple division methods are unlikely to as whole numbers, and simple division methods are unlikely to
produce this outcome for produce this outcome for al all (or any) states. Because the Constitution does not specify a particular (or any) states. Because the Constitution does not specify a particular
method for apportionment, several options have been considered and utilized throughout history. method for apportionment, several options have been considered and utilized throughout history.
When determining apportionment, parameters could be set for the number of seats in the House, When determining apportionment, parameters could be set for the number of seats in the House,
the population size of a district, or both.70 The Constitution, to an extent, addresses House size the population size of a district, or both.70 The Constitution, to an extent, addresses House size
and district size by requiring that each state receives at least one House seat and requiring that and district size by requiring that each state receives at least one House seat and requiring that
there can be no more than one Representative per every 30,000 persons.71 Yet these provisions there can be no more than one Representative per every 30,000 persons.71 Yet these provisions
provide littleprovide little practical guidance for what the size of the House or the size of a district should be. practical guidance for what the size of the House or the size of a district should be.
Based on the number of states and U.S. apportionment population from the 2010 Census, for Based on the number of states and U.S. apportionment population from the 2010 Census, for
example, the House could range from a minimum of 50 seats to a maximum size of over 10,000 example, the House could range from a minimum of 50 seats to a maximum size of over 10,000
seats. As a general principle, House size and district size are inversely related: a larger number of seats. As a general principle, House size and district size are inversely related: a larger number of
House seats means House seats means ~~smal er~~smaller population sizes for districts, and a population sizes for districts, and a ~~smal er~~smaller number of House seats number of House seats
means larger population sizes for districts. Attempts by the Framers and various Congresses to means larger population sizes for districts. Attempts by the Framers and various Congresses to
address apportionment reveal a number of perspectives on how best to create a representative address apportionment reveal a number of perspectives on how best to create a representative
legislature, along with politicallegislature, along with political and logistical considerations related to changes in the size of the and logistical considerations related to changes in the size of the
House.72House.72
Prioritizing Equal-Sized Districts or Preserving a Fixed House Size
An apportionment method prioritizing relatively equal district population size would establish a An apportionment method prioritizing relatively equal district population size would establish a
representation ratio, where there would be one Representative per representation ratio, where there would be one Representative per x number of persons. If the number of persons. If the
ratio remains the same across apportionment cycles, increases or decreases in the U.S. ratio remains the same across apportionment cycles, increases or decreases in the U.S.
apportionment population would result in corresponding increases or decreases to the total apportionment population would result in corresponding increases or decreases to the total
number of House seats. The representation ratio could also be adjusted to create larger or number of House seats. The representation ratio could also be adjusted to create larger or ~~smal er~~smaller
districts, in order to limit the magnitude of changes to the districts, in order to limit the magnitude of changes to the ~~overal~~ overall size of the House. If states size of the House. If states
receive fractional receive fractional ~~al ocations~~allocations of House seats and there is no constraint on the size of the House, a of House seats and there is no constraint on the size of the House, a
simple rounding rule could be utilizedsimple rounding rule could be utilized to arrive at a whole number of seats for the House to arrive at a whole number of seats for the House ~~overal~~ overall. .
A general example of an apportionment approach prioritizing relatively equal district size A general example of an apportionment approach prioritizing relatively equal district size
follows: follows:
1. determine an ideal 1. determine an ideal district population size, district population size, d; ;

70 For additional information, see Michael L. Balinski and70 For additional information, see Michael L. Balinski and H. Peyton Young, H. Peyton Young, Fair Representation: Meeting the Ideal of
One Man, One Vote (New(New Haven, CTHaven, CT : Yale University Press, 1982); and Efton Park, “: Yale University Press, 1982); and Efton Park, “ The Mathematics of The Mathematics of
Apportionment,” Apportionment,” University of Chicago Law School Roundtable, vol. 7, no. 1 (2000), pp. 227-237, available at , vol. 7, no. 1 (2000), pp. 227-237, available at
https://chicagounbound.uchicago.edu/roundtable/vol7/iss1/9/?. https://chicagounbound.uchicago.edu/roundtable/vol7/iss1/9/?.
71 In practice, each House district must also be geographically contained within a state’s boundaries;71 In practice, each House district must also be geographically contained within a state’s boundaries; states states ~~can not~~cannot share share
districts. districts.
72 For example, the first amendment proposed by James Madison for the Bill 72 For example, the first amendment proposed by James Madison for the Bill of Rights addressedof Rights addressed apportionment, but it apportionment, but it
waswas not ratified. Seenot ratified. See Akhil ReedAkhil Reed Amar, Amar, The Bill of Rights (New (New Haven, CTHaven, CT : Yale University Press, 1998), pp. 8: Yale University Press, 1998), pp. 8 -17; -17;
and Rosemarie Zagarri, and Rosemarie Zagarri, The Politics of Size: Representation in the United States, 1776 -1850 (Ithaca, NY: Cornell (Ithaca, NY: Cornell
University Press, 1987). University Press, 1987).
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2. divide 2. divide each state’s apportionment population, each state’s apportionment population, ps1, s1, ps2 …s2 … ps50, by s50, by d to determine to determine
how many House seats a state would be entitled to (its “quota” of seats), how many House seats a state would be entitled to (its “quota” of seats), q; and ; and
3. determine a rounding rule to apply for states in which 3. determine a rounding rule to apply for states in which q is not a whole number.73 is not a whole number.73
Until Until the early 20th century, the size of the House the early 20th century, the size of the House ~~general y~~generally increased with each apportionment, increased with each apportionment,
due to the addition of new states and population growth,74 but today, the number of House seats is due to the addition of new states and population growth,74 but today, the number of House seats is
set at 435 by federal statute.75 Arguments to expand the House have included expanding the range set at 435 by federal statute.75 Arguments to expand the House have included expanding the range
of interests that House Members would represent and ensuring that Members remained of interests that House Members would represent and ensuring that Members remained
knowledgeable about local issues. Yet concerns have also been raised that it would not be feasible knowledgeable about local issues. Yet concerns have also been raised that it would not be feasible
to increase the House size apace with national population growth.76 to increase the House size apace with national population growth.76
To be sure that a particular apportionment conforms to a specified size of the House, each state To be sure that a particular apportionment conforms to a specified size of the House, each state
must receive a whole number of seats, and the sum of must receive a whole number of seats, and the sum of al all states’ seats must equal the desired total states’ seats must equal the desired total
House size. Many apportionment approaches vary on how to address fractional seats, as House size. Many apportionment approaches vary on how to address fractional seats, as
remainders remainders ~~wil~~ will often result when calculating state seat quotas. A general example of an often result when calculating state seat quotas. A general example of an
apportionment approach to reach a certain House size follows: apportionment approach to reach a certain House size follows:
1. a set number of House seats, 1. a set number of House seats, H, is agreed upon; , is agreed upon;
2. divide 2. divide the nationalthe national apportionment population, apportionment population, pUSA, by , by H to determine an “ideal” to determine an “ideal”
or average district population size, or average district population size, d, also known as the “initial divisor”; , also known as the “initial divisor”;
3. divide 3. divide each state’s apportionment population, each state’s apportionment population, ps1, s1, ps2 …s2 … ps50, by s50, by d to determine to determine
how many House seats a state would be entitled to (its “quota” of seats), how many House seats a state would be entitled to (its “quota” of seats), q; ;
4. determine a rounding rule to apply to any 4. determine a rounding rule to apply to any q values that are not whole numbers (to values that are not whole numbers (to
represent actual House seats, which cannot be divided);77 and represent actual House seats, which cannot be divided);77 and
5. add these rounded (or adjusted), 5. add these rounded (or adjusted), q values; if this sum does not equal values; if this sum does not equal H, determine , determine
a method to adjust state quotas so that the sum of the resulting a method to adjust state quotas so that the sum of the resulting q values equals values equals H. .
The following discussions provide an introduction to several methods that have been used for The following discussions provide an introduction to several methods that have been used for
congressional apportionment in the United States. To congressional apportionment in the United States. To ~~il ustrate~~illustrate how these methods work, for each how these methods work, for each
method an imaginary example is provided in the accompanying table, in which the size of the method an imaginary example is provided in the accompanying table, in which the size of the
House is fixed at 20 Members and the seats are divided among four states (states A, B, C, and D) House is fixed at 20 Members and the seats are divided among four states (states A, B, C, and D)
with the populations specified in the tables. with the populations specified in the tables.
Hamilton/Vinton Method (Ranking Fractional Remainders)
Congress considered various methods of apportionment after the first census of 1790 and passed Congress considered various methods of apportionment after the first census of 1790 and passed
an initialan initial apportionment apportionment ~~bil~~ bill in 1792 that would have utilized what is now known as the in 1792 that would have utilized what is now known as the
Hamilton/VintonHamilton/Vinton method. President George Washington, however, exercised his first veto on the method. President George Washington, however, exercised his first veto on the
measure, in part, because the resulting apportionment calculations would have violated the measure, in part, because the resulting apportionment calculations would have violated the

73 An additional decision rule73 An additional decision rule may also be necessary to ensure that each state receives at least one House seat, as may also be necessary to ensure that each state receives at least one House seat, as
requiredrequired by the Constitution. by the Constitution.
74 An exception occurred in 1842, when the number of House seats decreased; 74 An exception occurred in 1842, when the number of House seats decreased; for additional details, see Martin H. for additional details, see Martin H.
Quitt, “Congressional (Partisan) Constitutionalism: Quitt, “Congressional (Partisan) Constitutionalism: ~~T he~~The Apportionment Act Debate of 1842 and 1844,” Apportionment Act Debate of 1842 and 1844,” Journal of the
Early Republic, vol. 28, no. 4 (Winter 2008), pp. 627, vol. 28, no. 4 (Winter 2008), pp. 627 -651. -651.
75 P.L. 62-5, August 8, 1911, 37 Stat. 13, Ch. 5. 75 P.L. 62-5, August 8, 1911, 37 Stat. 13, Ch. 5.
76 For some of these considerations, see summary provided in Christopher St. John Yates, “A House of Our Own76 For some of these considerations, see summary provided in Christopher St. John Yates, “A House of Our Own or a or a
HouseHouse We’ve Outgrown,” We’ve Outgrown,” Columbia Journal of Law and Social Problems, vol. 25 (1992), pp. 174-187. , vol. 25 (1992), pp. 174-187.
77 An additional decision rule77 An additional decision rule may also be necessary to ensure that each state receives at least one House seat, as may also be necessary to ensure that each state receives at least one House seat, as
requiredrequired by the Constitution. by the Constitution.
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requirement of at least 30,000 persons per district for multiple states.78 Representative Samuel requirement of at least 30,000 persons per district for multiple states.78 Representative Samuel
Vinton later introduced legislation proposing this method, which was enacted, and this Vinton later introduced legislation proposing this method, which was enacted, and this
apportionment method was first used in 1850 and continued to inform apportionment apportionment method was first used in 1850 and continued to inform apportionment
considerations throughout the rest of the 19th century, in conjunction with the Webster method considerations throughout the rest of the 19th century, in conjunction with the Webster method
(discussed below). The Hamilton/Vinton method is based on a fixed House size, (discussed below). The Hamilton/Vinton method is based on a fixed House size, H. Each state . Each state
receives the whole number of seats in its quota, receives the whole number of seats in its quota, q, of seats. The remainders from , of seats. The remainders from q are rank- are rank-
ordered from largest to ordered from largest to ~~smal est~~smallest, and any additional House seats are apportioned to the states with , and any additional House seats are apportioned to the states with
the largest remainders. the largest remainders.
Table A-1. Hamilton/Vinton Method—Sample Apportionment
House size ( House size (H) = 20 [Fixed] ) = 20 [Fixed]
Step 1: Find whole number
of seats using d (round
Step 2: Apportion additional seats in order of

down any q remainder)
largest fractional remainders
Additional
Total
State
Population
Quota (q)a
Seats
Remainder
Rank
Seat(s)
Seats
A A
2,560 2,560
2,560 / 594.1 = 4.31 2,560 / 594.1 = 4.31
4 4
.31 .31
4th 4th
0 0
4 4
B B
3,315 3,315
3,315 / 594.1 = 5.58 3,315 / 594.1 = 5.58
5 5
.58 .58
2nd 2nd
1 1
6 6
C C
995 995
995 / 594.1 = 1.67 995 / 594.1 = 1.67
1 1
.67 .67
1st 1st
1 1
2 2
D D
5,012 5,012
5,012 / 594.1 = 8.44 5,012 / 594.1 = 8.44
8 8
.44 .44
3rd 3rd
0 0
8 8
Total
11,882 11,882

18 18

2 2
20 20
Source: Adapted from U.S. Census Bureau, “Methods of Apportionment,”Adapted from U.S. Census Bureau, “Methods of Apportionment,” at https://www.census.gov/history/at https://www.census.gov/history/
www/reference/apportionment/methods_of_apportionment.html. www/reference/apportionment/methods_of_apportionment.html.
a. The denominator here is calculated by dividing the national apportionment population (a. The denominator here is calculated by dividing the national apportionment population ( pUSA = 11,882) by the = 11,882) by the
number of House seats ( number of House seats (H = 20).= 20).
Jefferson Method (Largest Divisors)
Following the presidential veto of the Hamilton method, Congress adopted the Jefferson method Following the presidential veto of the Hamilton method, Congress adopted the Jefferson method
of apportionment, which was used from 1792 to 1832. The Jefferson method for apportionment is of apportionment, which was used from 1792 to 1832. The Jefferson method for apportionment is
based on a fixed House size, based on a fixed House size, H, and each state’s quota of seats, , and each state’s quota of seats, q, is rounded down to the nearest , is rounded down to the nearest
whole number. Often, the sum of the rounded-down whole number. Often, the sum of the rounded-down q values is less than values is less than H. When this occurs, . When this occurs,
divisor values divisor values ~~smal er~~smaller than than d are tested until an adjusted divisor, are tested until an adjusted divisor, dadj, is found that results in a set adj, is found that results in a set
of of q values which, when rounded down, sum to values which, when rounded down, sum to H. .

78 Although the method contained in the bill was78 Although the method contained in the bill was a product of congressional debate, it has become associated with a product of congressional debate, it has become associated with
Secretary of State Alexander Hamilton. President Washington sought opinions from his Cabinet on the apportionment Secretary of State Alexander Hamilton. President Washington sought opinions from his Cabinet on the apportionment
bill,bill, and Hamilton wrote in support of this approach; Hamilton’s letter is available at https://founders.archives.gov/and Hamilton wrote in support of this approach; Hamilton’s letter is available at https://founders.archives.gov/
documents/Hamilton/01-11-02-0189-0002. See also Balinski and Young, ch. 3. documents/Hamilton/01-11-02-0189-0002. See also Balinski and Young, ch. 3.
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Table A-2. Jefferson Method—Sample Apportionment
House size ( House size (H) = 20 [Fixed] = 20 [Fixed]
Step 1: Find seats if apportioned
using initial divisor, d (round
Step 2: Apportion seats using

down any q remainder)
adjusted divisor, dadja
State
Population
Quota (q)b
Seats
Quota
Total Seats
A A
2,560 2,560
2,560 / 594.1 = 4.31 2,560 / 594.1 = 4.31
4 4
2,560 / 550 = 4.65 2,560 / 550 = 4.65
4 4
B B
3,315 3,315
3,315 / 594.1 = 5.58 3,315 / 594.1 = 5.58
5 5
3,315 / 550 = 6.03 3,315 / 550 = 6.03
6 6
C C
995 995
995 / 594.1 = 1.67 995 / 594.1 = 1.67
1 1
995 / 550 = 1.81 995 / 550 = 1.81
1 1
D D
5,012 5,012
5,012 / 594.1 = 8.44 5,012 / 594.1 = 8.44
8 8
5,012 / 550 = 9.11 5,012 / 550 = 9.11
9 9
Total
11,882 11,882

18 18

20 20
Source: Adapted from U.S. Census Bureau, “Methods of Apportionment,” Adapted from U.S. Census Bureau, “Methods of Apportionment,” at https://www.census.gov/history/at https://www.census.gov/history/
www/reference/apportionment/methods_of_apportionment.html. www/reference/apportionment/methods_of_apportionment.html.
a. The regular divisor,a. The regular divisor, d, is often used as a starting point to inform, is often used as a starting point to inform what values could work for an adjusted what values could work for an adjusted
divisor, divisor, dadj. Here,adj. Here, 550 is used as the adjusted divisor550 is used as the adjusted divisor value, but any integer between 513 or 552 would also value, but any integer between 513 or 552 would also
produce a seriesproduce a series of of q values that, when rounded down, sum to the total House size of 20 seats. values that, when rounded down, sum to the total House size of 20 seats.
b. The denominator here is calculated by dividing the national apportionment population ( b. The denominator here is calculated by dividing the national apportionment population (pUSA = 11,882) by the = 11,882) by the
number of House seats ( number of House seats (H = 20).= 20).
Webster Method (Major Fractions)
Some believed that the Jefferson method favored large states, and the Webster method was an Some believed that the Jefferson method favored large states, and the Webster method was an
approach first used for apportionment in 1842 and last used for apportionment following the 1930 approach first used for apportionment in 1842 and last used for apportionment following the 1930
census. The Webster method is similar to the Hamilton/Vintoncensus. The Webster method is similar to the Hamilton/Vinton method but differs in how it method but differs in how it
addresses remainders of seats. Each state receives the whole number of seats in its quota, addresses remainders of seats. Each state receives the whole number of seats in its quota, q; then, ; then,
q remainders greater than or equal to 0.5 are rounded up to the next whole number, and those remainders greater than or equal to 0.5 are rounded up to the next whole number, and those
states receive an additional seat. The example provided istates receive an additional seat. The example provided in Table A-3 happens to result in the happens to result in the
same number of House seats as the other examples in this appendix, which treat the House size, same number of House seats as the other examples in this appendix, which treat the House size,
H, as fixed at 20 seats, but performing these initial calculations under the Webster method could , as fixed at 20 seats, but performing these initial calculations under the Webster method could
result in a subsequent adjustment to the number of House seats.79 If the House size remains fixed, result in a subsequent adjustment to the number of House seats.79 If the House size remains fixed,
and the initialand the initial sum of seats produced by the Webster method does not equal the desired number of sum of seats produced by the Webster method does not equal the desired number of
seats, an adjusted divisor, dadj, can be used to calculate seats, an adjusted divisor, dadj, can be used to calculate q values that, when rounded and summed, values that, when rounded and summed,
result in a specific House size. result in a specific House size.

79 For example, the rounding rule could79 For example, the rounding rule could result in a larger number of House seats (i.e., if each state’s result in a larger number of House seats (i.e., if each state’s q had a remainder had a remainder
of 0.5 or above) or smaller number of Houseof 0.5 or above) or smaller number of House seats (i.e., if each state’s seats (i.e., if each state’s q had a remainder lower than 0.5) than expected. had a remainder lower than 0.5) than expected.
Exceptions to the Webster method “rule” wouldExceptions to the Webster method “rule” would have to be made for any state receiving a quota of lesshave to be made for any state receiving a quota of less than 0.5 so that than 0.5 so that
the state wouldthe state would receive one Housereceive one House seat, as requiredseat, as required by the Constitution.by the Constitution.
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Table A-3. Webster Method—Sample Apportionment
Step 1: Find whole number of
seats using d (round down any
Step 2: Apportion additional seat to state if

q remainder)
quota remainder ≥ 0.5
State
Population
Quota (q)a
Seats
Remainder
~~Additional~~ Additional Seat
Total Seats
A A
2,560 2,560
2,560 / 594.1 = 4.31 2,560 / 594.1 = 4.31
4 4
.31 .31
0 0
4 4
B B
3,315 3,315
3,315 / 594.1 = 5.58 3,315 / 594.1 = 5.58
5 5
.58 .58
1 1
6 6
C C
995 995
995 / 594.1 = 1.67 995 / 594.1 = 1.67
1 1
.67 .67
1 1
2 2
D D
5,012 5,012
5,012 / 594.1 = 8.44 5,012 / 594.1 = 8.44
8 8
.44 .44
0 0
8 8
Total
11,882 11,882

18 18

2 2
20 20
Source: Adapted from U.S. Census Bureau, “Methods of Apportionment,” Adapted from U.S. Census Bureau, “Methods of Apportionment,” at https://www.census.gov/history/at https://www.census.gov/history/
www/reference/apportionment/methods_of_apportionment.html. www/reference/apportionment/methods_of_apportionment.html.
a. The denominator here is calculated by dividing the national apportionment population (pUSA = 11,882) by a. The denominator here is calculated by dividing the national apportionment population (pUSA = 11,882) by
the number of House seats (H = 20). the number of House seats (H = 20).
Huntington-Hill Method (Method of Equal Proportions)
In addition to treating large and In addition to treating large and ~~smal~~ small states similarly, some have also believed that an states similarly, some have also believed that an
apportionment method should minimize percentage differences in district population sizes (across apportionment method should minimize percentage differences in district population sizes (across
states) as much as possible. The method of equal proportions, also known as the Huntington-states) as much as possible. The method of equal proportions, also known as the Huntington-~~Hil~~
Hill method, seeks to achieve this objective, and has been used for method, seeks to achieve this objective, and has been used for al all House apportionments since House apportionments since
1941. This method differs from the Webster method by rounding up remainders for a state’s 1941. This method differs from the Webster method by rounding up remainders for a state’s
quota, quota, q, at the geometric mean, , at the geometric mean, G, rather than at the arithmetic mean. The geometric mean is , rather than at the arithmetic mean. The geometric mean is
found by multiplying two successive numbers together, then taking the square root of their found by multiplying two successive numbers together, then taking the square root of their
product; here, the successive numbers represent a state’s product; here, the successive numbers represent a state’s q rounded down to the nearest whole rounded down to the nearest whole
number (its “lower” quota) and a state’s number (its “lower” quota) and a state’s q rounded up to the nearest whole number (its “upper” rounded up to the nearest whole number (its “upper”
quota). Each state receives its “lower” quota of seats and then may receive an additional seat if its quota). Each state receives its “lower” quota of seats and then may receive an additional seat if its
quota, quota, q, is greater than or equal to its geometric mean, , is greater than or equal to its geometric mean, G. .
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Table A-4. Huntington-~~Hil~~ Hill Method—Sample Apportionment
House size ( House size (H) = 20 [Fixed] = 20 [Fixed]
Step 1: Find lower quota (round
down any q remainder) ~~and~~ and upper
Step 2: Apportion additional seat to

quota (round up up any q remainder)
state if quota ≥ geometric mean
Lower
Upper
Geometric
Additional Seat
Total
State
Population
Quota (q)a
Quota
Quota
Mean (G)
(If q ≥ G)
Seats
A A
2,560 2,560
2,560 / 594.1 = 4.31 4 2,560 / 594.1 = 4.31 4
5 5
√(4x5) = 4.47 √(4x5) = 4.47
0 0
4 4
B B
3,315 3,315
3,315 / 594.1 = 5.58 5 3,315 / 594.1 = 5.58 5
6 6
√(5x6) = 5.48 √(5x6) = 5.48
1 1
6 6
C C
995 995
995 / 594.1 = 1.67 995 / 594.1 = 1.67
1 1
2 2
√(1x2) = 1.41 √(1x2) = 1.41
1 1
2 2
D D
5,012 5,012
5,012 / 594.1 = 8.44 8 5,012 / 594.1 = 8.44 8
9 9
√(8x9) = 8.49 √(8x9) = 8.49
0 0
8 8
Total
11,882 11,882

18 18
22 22

2 2
20 20
Source: Adapted from U.S. Census Bureau, “Methods of Apportionment,” Adapted from U.S. Census Bureau, “Methods of Apportionment,” at https://www.census.gov/history/at https://www.census.gov/history/
www/reference/apportionment/methods_of_apportionment.html.www/reference/apportionment/methods_of_apportionment.html.
a. The denominator here is calculated by dividing the national apportionment population (pUSA = 11,882) by a. The denominator here is calculated by dividing the national apportionment population (pUSA = 11,882) by
the number of House seats (H = 20). the number of House seats (H = 20).
The initial The initial calculation for a state’s quota, calculation for a state’s quota, q, under the method of equal proportions, is made by , under the method of equal proportions, is made by
using the “ideal”using the “ideal” district size, district size, d, as the divisor, as the divisor. Table A-4 provides a sample apportionment in provides a sample apportionment in
which the sum of the rounded geometric means happens to result in the desired House size, which the sum of the rounded geometric means happens to result in the desired House size, H, of , of
20 seats, but, in practice, this often does not occur. If the sum of the rounded geometric means for 20 seats, but, in practice, this often does not occur. If the sum of the rounded geometric means for
each state does not result in the desired number of House seats, there is an additional step: seats each state does not result in the desired number of House seats, there is an additional step: seats
can be apportioned using a can be apportioned using a priority list, which , which ~~essential y~~essentially ranks each state’s claim to the “next” ranks each state’s claim to the “next”
House seat apportioned (i.e., the 51st-435th seats), after each state receives the one seat it is House seat apportioned (i.e., the 51st-435th seats), after each state receives the one seat it is
~~constitutional y~~constitutionally entitled to. entitled to.
To generate a priority list, each state’s apportionment population is multiplied by a series of To generate a priority list, each state’s apportionment population is multiplied by a series of
multipliermultiplier values. The multiplier values are created using the reciprocal of the geometric mean values. The multiplier values are created using the reciprocal of the geometric mean
associated with each potential successive seat number for the state (above its associated with each potential successive seat number for the state (above its ~~constitutional y~~
constitutionally mandated first seat). For example, the multiplier value for a second House seat in any state would mandated first seat). For example, the multiplier value for a second House seat in any state would
be 1/√(1 x 2) or 0.707, the multiplier for a third House seat would be √(2 x 3) or 0.408, and so be 1/√(1 x 2) or 0.707, the multiplier for a third House seat would be √(2 x 3) or 0.408, and so
on.80 The products that result from multiplying these values by each state’s apportionment on.80 The products that result from multiplying these values by each state’s apportionment
population are ranked from largest to population are ranked from largest to ~~smal est~~smallest to create the priority list, and seats are distributed to create the priority list, and seats are distributed
until until H number of seats (currently 385, the number needed to get to a total of 435 seats once each number of seats (currently 385, the number needed to get to a total of 435 seats once each
of the 50 states receives its of the 50 states receives its ~~constitutional y~~constitutionally required seat) have been apportioned. required seat) have been apportioned.

~~80 T he Census Bureau~~ 80 The Census Bureau typically calculates and provides a list of priority values for each apportionment; for the 2010 typically calculates and provides a list of priority values for each apportionment; for the 2010
priority list, see U.S.priority list, see U.S. ~~Census Bureau, “~~ Census Bureau, “2010 Census Apportionment Results,” December 2010, at 2010 Census Apportionment Results,” December 2010, at
https://www.census.gov/data/tables/2010/dec/2010-apportionment-data.html. https://www.census.gov/data/tables/2010/dec/2010-apportionment-data.html.
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Table A-5. Sample Priority Values and Resulting Priority List for Selected Values
House size ( House size (H) = 20 [Fixed] = 20 [Fixed]

~~2nd~~2 nd
3rd
4th
5th
6th
7th
8th
9th

State
Population
Seat
Seat
Seat
Seat
~~Seat~~
~~Seat~~
~~Seat~~
Seat Seat Seat Seat

Priority Valuesa

A A
2,560 2,560
1,810 1,810
1,045 1,045
739 739
572 572
467 467
395 395
342 342
302 302

B B
3,315 3,315
2,344 2,344
1,353 1,353
957 957
741 741
605 605
512 512
443 443
391 391

C C
995 995
704 704
406 406
287 287
222 222
182 182
154 154
133 133
117 117

D D
5,012 5,012
3,544 3,544
2,046 2,046
1,447 1,447
1,121 915 1,121 915
773 773
670 670
591 591

Total
Corresponding Priority List Rankingb
Seats
A A
2,560 2,560
4
8
13
18 18
22 22
27 27
32 32
36 36
4 4
B B
3,315 3,315
2
6
9
12
16
20 20
23 23
28 28
6 6
C C
995 995
14
25 25
38 38
51 51
62 62
75 75
86 86
98 98
2 2
D D
5,012 5,012
1
3
5
7
10
11
15
17 17
8 8
Total
11,882 11,882

20 20
Source: CRS calculation. CRS calculation.
a. Each prioritya. Each priority value is calculated by multiplying the state’s apportionment population by a multiplier, value is calculated by multiplying the state’s apportionment population by a multiplier,
representing the reciprocal representing the reciprocal ~~geometric~~ geometric mean of the last seat apportioned and the next seat to be apportioned. mean of the last seat apportioned and the next seat to be apportioned.
For seat number, For seat number, n, the multiplier, the multiplier is 1 / (√((n-1) x n). For a list of multipliers,is 1 / (√((n-1) x n). For a list of multipliers, see U.S. Census Bureau, see U.S. Census Bureau,
“Apportionment: Table of Multipliers“Apportionment: Table of Multipliers using the Method of Equal Proportions,”using the Method of Equal Proportions,” October 17, 2000, at October 17, 2000, at
https://www.census.gov/population/apportionment/files/atable.txt.https://www.census.gov/population/apportionment/files/atable.txt. In this table, priorityIn this table, priority values are rounded to values are rounded to
the nearest whole number. the nearest whole number.
b. Values italicized and in bold represent b. Values italicized and in bold represent the 16 remainingthe 16 remaining seats to be apportioned, after each state receives seats to be apportioned, after each state receives
one seat as one seat as ~~constitutional y required~~ constitutionally required and assuming a House size of 20. Larger values in this table are not and assuming a House size of 20. Larger values in this table are not
consecutive because this table only includes rankings associated with the first nine additional seats to be consecutive because this table only includes rankings associated with the first nine additional seats to be
apportioned. Largerapportioned. Larger states could be ranked higher and entitled to additional seats (above nine) before states could be ranked higher and entitled to additional seats (above nine) before ~~smal er~~smaller
states receivestates receive any additional seats. In this example,any additional seats. In this example, if the priorityif the priority list table continued to display values for list table continued to display values for
additional seats, State D would be ranked 19th and would receiveadditional seats, State D would be ranked 19th and would receive its 10th seat before State B receivesits 10th seat before State B receives its 7th its 7th
seat (ranked 20th); State D is also ranked 21st and would receiveseat (ranked 20th); State D is also ranked 21st and would receive its 11th seat before State A receivesits 11th seat before State A receives its 6th its 6th
seat (ranked 22nd). seat (ranked 22nd).

Author Information

Sarah J. Eckman Sarah J. Eckman

Analyst in American National Government Analyst in American National Government

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Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan
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than public understanding of information that has been provided by CRS to Members of Congress in than public understanding of information that has been provided by CRS to Members of Congress in
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