Order Code RS21729
Updated November 9, 2006
CRS Report for Congress
Received through the CRS Web
U.S. International Borders: Brief Facts
Janice Cheryl Beaver
Information Research Specialist
Knowledge Services Group
Summary
This report provides information on the international boundaries that the United
States shares with Canada and Mexico. Included are data on land and water boundaries
for the northern Canadian border and the southern Mexican border, as well as the
international boundaries for the U.S. states that border these countries. Coastline figures
for the continental United States, Alaska, Hawaii, the Great Lakes, and extraterritorial
areas are also included. For additional information on current border security issues, see
CRS Report RS22026, Border Security: The San Diego Fence, by Blas Nunez-Neto and
Stephen R Vina; CRS Report RL33659, Border Security: Barriers Along the U.S.
International Border, by Blas Nunez-Neto and Stephen R. Vina; CRS Report RL33181,
Immigration Related Border Security Legislation in the 109th Congress, by Blas Nunez-
Neto and Janice Cheryl Beaver; CRS Report RL33353, Civilian Patrols Along the
Border: Legal and Policy Issues, by Blas Nunez-Neto and Stephen R. Vina, CRS Report
RS22443, Border Security and Military Support: Legal Authorizations and Restrictions,
by Stephen R. Vina; CRS Report RL33106, Border Security and the Southwest Border:
Background, Legislation, and Issues, by Lisa M. Seghetti, coordinator; CRS Report
RL31826, Protecting Our Perimeter: ‘Border Searches’ under the Fourth Amendment,
by Stephen Vina; and CRS Report RL32399, Border Security: Inspections Practices,
Policies, and Issues, by Ruth Ellen Wasem, coordinator. This report will be updated as
needed.
Canadian and Mexican Borders
According to the U.S. Geological Survey (USGS), the length of the International
Boundary line of the U.S.-Canadian border, excluding Alaska, is approximately 3,987
miles, while the length of the U.S.-Mexican border is estimated at 1,933 miles. The
length of the Alaska-Canada border alone is 1,538 miles. The tables below list the 13
U.S. states that share international boundaries with Canada and the four states that share
an international border with Mexico, with information from the International Boundary
Commission and the U.S. Geological Survey.
Congressional Research Service ˜ The Library of Congress

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Table 1. Length of U.S.-Canada Land and
Water Boundary by State
(in descending order in miles)
State
Boundary length
Alaska
1,538
Michigan
721
Maine
611
Minnesota
547
Montana
545
New York
445
Washington
427
North Dakota
310
Ohio
146
Vermont
90
New Hampshire
58
Idaho
45
Pennsylvania
42
Total
5,525
Source: International Boundary Commission. [http://www.internationalboundarycommission.org/
ibcpg2.htm]
Table 2. Length of U.S.-Mexico Land and Water Boundary, by State
(in miles)
State
Border Length
(from east to west)
(including along the Rio Grande)
Texas
1,241.0
Arizona (including 19.1 miles
372.5
along the Colorado River)
New Mexico
179.5
California
140.4
Total
1,933.4
Source: U.S. Geological Survey and CRS phone consultation with USGS library.
Note: The border area in the United States consists of four states.
U.S. Coastline
The National Oceanic and Atmospheric Administration (NOAA) has surveyed the
coastline of the continental United States, Alaska, and Hawaii several times. The current
figures for the coastline are the results of the measurements done originally in 1915 and

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updated several times thereafter. These figures reflect the general outline of the seacoast.
The figures for Alaska reflect a 1961 remeasurement.
It is important to note that boundary and coastline distances can differ significantly
based on the scale used on the maps or charts. The Canadian and Mexican international
borders are less problematic than the coastline measures because there are long stretches
that are straight, such as the nearly 900-mile section of the U.S.-Canadian border along
the 49th parallel.
Coastline measurements are more difficult because of the effects of tides and the
necessarily arbitrary decisions that must be made about measuring bays, coves, islands,
and inlets leading to streams and rivers. The “general coastline” data in this report are
based on large scale nautical charts, resulting in a coastline measure for the 50 states
totaling12,383 miles. Another measure using smaller scale nautical charts more than
doubles this measurement to 29,093 miles, while the figures used by the NOAA in
administering the Coastal Zone Management program (16 U.S.C. §1451) come to 88,612
miles (not including the Great Lakes).
Table 3. Length of the U.S. Coastline
(in miles)
United States
General Coastline
Maine
228
New Hampshire
13
Massachusetts
192
Rhode Island
40
Connecticut
96a
New York
127
New Jersey
130
Delaware
28
Maryland
31
Virginia
112
North Carolina
301
South Carolina
187
Georgia
100
Florida
1,350
Alabama
53
Mississippi
44
Louisiana
397
Texas
367
California
840
Oregon
296

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United States
General Coastline
Washington
157
Alaska
6,640
Hawaii
750
Total
12,479
Source: U.S. Department of Commerce, National Oceanic and Atmospheric Administration, The Coastline
of the United States, 1975.
Notes: This table measures the U.S. coastline from northeast around the United States to northwest.
a. The number for Connecticut is not in the original source cited above; this figure represents the tidal
shoreline (general, not detailed) used by David Huckabee, CRS specialist in American national
government, who has written about coastline measurement.
Variations in shoreline figures appear because of natural occurrences including bays
and inlets, and in differing methods of measurement. In addition to the difficulties
mentioned above concerning calculation of lengths of coastline, one encounters a similar
problem when attempting to measure shoreline (i.e., that area of length along the Great
Lakes).
Great Lakes Shorelines
These shoreline lengths were measured in 1970 by the International Coordinating
Committee on the Great Lakes Basic Hydraulic and Hydrologic Data.
Table 4. Great Lakes Shorelines and Connecting Rivers
(in miles)
Body of Water
U.S. Shoreline
Lake Superior
1,250
St. Marys River
120
Lake Michigan
1,640
Lake Huron
840
St. Clair River
30
Lake St. Clair
140
Detroit River
70
Lake Erie
470
Niagara River
70
Lake Ontario
330
Total
4,960
St. Lawrence River (above Iroquois Dam)
220
St. Lawrence River (above Power Dam)
320
Source: U.S. Department of Commerce, National Oceanic and Atmospheric Administration, The Coastline
of the United States, 1975.

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Selected Print Sources
Shalowitz, Aaron L. Shore and Sea Boundaries, v. 2. Washington: U.S. Dept. of
Commerce, Coast and Geodetic Survey, 1964. Coast and Geodetic Survey
Publication 10-1.
U.S. Census Bureau. Statistical Abstract of the United States 2002. Washington: GPO,
2002.
U.S. Department of Commerce, National Oceanic and Atmospheric Administration. The
Coastline of the United States, 1975.
Van Zandt, Franklin K. Boundaries of the United States and the Several States.
Washington: GPO, 1976. Geological Survey Professional Paper 909.
The World Almanac and Book of Facts 2005.
Selected Internet Sources
International Boundary and Water Commission (IBWC) United States and Mexico
[http://www.ibwc.state.gov]

This website has historical information on the two treaties — the Guadalupe Hidalgo
Treaty of February 2,1848, and the Treaty of December 30, 1853 — between the United
States and Mexico that set the international boundary between the two countries. Also
included is information on additional conventions and treaties between the two nations
on maintaining the Rio Grande and Colorado Rivers, as well as current IBWC reports and
solutions for boundary and water problems.
International Boundary Commission between Canada and the United States
[http://www.internationalboundarycommission.org]
This website contains information on the Treaty of 1908 between the United States
and Canada that completed the mapping of the international boundary from the Atlantic
Ocean to the Pacific Ocean. Information on U.S.-Canadian border history and boundary
markings along open vistas is also included.
This report, which was originally authored by CRS Information Specialist Barbara
Torreon, will be updated as needed.

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