CRS INSIGHT Prepared for Members and Committees of Congress

INSIGHTi

Congressional District Geography Workbook: An Interactive Tool for Congressional Users

July 23, 2024

This Insight accompanies the Congressional District Geography Workbook, a Microsoft Excel file that congressional users can download from CRS.gov. The workbook provides information about U.S. House districts as configured in the 118^th Congress (2023-2024).

Workbook Overview and Layout

The Congressional District Geography Workbook contains selected information about geographic areas and features located inside each of the 435 congressional districts across all 50 states. It also includes information for the District of Columbia, Puerto Rico, American Samoa, Guam, Northern Mariana Islands, and U.S. Virgin Islands.

The 12 available categories of geographic areas and features are

• counties and equivalent entities such as Louisiana parishes, Connecticut planning regions, and cities that are independent of a county;

• county subdivisions, including minor civil divisions such as townships and Census County Divisions (CCDs);

• places, both municipalities such as cities and unincorporated Census Designated Places (CDPs);

• federal depository libraries;

• military installations, ranges, and training areas;

• national parks, including national monuments and other National Park System units;

• Native American areas, including federal reservations and other tribal lands;

• postsecondary schools, including colleges and universities;

• private schools;

• public schools;

• school districts; and

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• ZIP codes.

A geographic area or feature is associated with a specific congressional district when it is located fully or partly inside that district’s boundaries. Each area or feature may be located entirely within a single district or split between two or more districts.

The workbook, when downloaded and opened in Microsoft Excel, contains five sheets that can be accessed via tabs at the bottom of the screen:

• “Workbook Information” contains a table of contents and background information.

• “What’s In Your District” contains a pivot table. Users can select a state/territory and then a district to generate a list of geographic areas and features in that district. An Export Selection button allows users to quickly copy a district’s list into a new spreadsheet.

• “Complete Data Table” contains all the underlying information for the districts that is summarized in the pivot table. It has nearly 283,000 rows of data. Filters can be used to isolate a specific feature or area and determine which district(s) it is in.

• “Maps” contains hyperlinks to U.S. Census Bureau wall maps for each state and district, as well as a national-level map.

• “Statistics” contains hyperlinks to Census Bureau statistical profiles for each district on the data.census.gov platform.

The workbook sheets are password-protected to prevent accidental deletions or other changes to the file.

CRS can provide Members and congressional staffers with additional analysis and information (e.g., the extent of overlaps for areas or features that are split among more than one district) on request.

Please note that some district-level maps produced by the Census Bureau may contain outdated information about the Member representing that district, where the district recently had a special election or a vacancy occurred. In addition, a known bug on the data.census.gov website may result in some district statistical profile pages reverting to district boundaries used in the 116^th Congress.

Data Sources and Methodology

Unless otherwise noted, CRS acquired data from the sources described below in May and June 2024. These datasets were the most recent available, though they may have been compiled and updated at different times.

The Census Bureau provides information about counties, county subdivisions, Native American areas, places, and school districts via its Congressional District Relationship Files. These text-based tables contain crosswalks between congressional districts and geographic areas used in the 2020 census. CRS used national-level 2020 118^th Congressional District Relationship Files, supplemented by a 2022 118^th Congressional District to 2022 County file for Connecticut. For additional information on Native American areas, see CRS Report R48107, Selected Tribal Lands in 118th Congressional Districts, by Mainon A. Schwartz and Mariel J. Murray.

The National Center for Education Statistics (NCES), which is part of the Department of Education, provides spatial coordinates for public schools, private schools, and postsecondary institutions via its Education Demographic and Geographic Estimates. CRS used the tigris and sf packages in the R statistical programming language to match each school to a congressional district based on the longitude and latitude coordinates provided by NCES. The most recent files available were 2022-2023 data for public and postsecondary schools and 2021-2022 data for private schools. The Private School dataset does not include schools in U.S. territories. Because postsecondary institutions are represented by point locations, congressional-district assignments may not capture the full extent of a college or university’s

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campus. In addition, the Postsecondary Institution category may include administrative offices that are not necessarily associated with student populations.

The Department of Defense provided information directly to CRS in January 2024 about military installations in each congressional district. This category includes ranges and training areas. The source dataset excludes some facilities due to national security concerns; relatively small facilities, including many National Guard and Reserve sites; and U.S. Coast Guard facilities, which fall under the Department of Homeland Security.

The National Park Service provided information directly to CRS in January 2024 about national parks and other National Park System units, such as historic sites and battlefields, in each congressional district.

The Government Publishing Office provides information about federal depository libraries in each congressional district via its Federal Depository Library Directory.

CRS matched five-digit ZIP codes to congressional districts using GIS software and data from Esri. These include ZIP codes that represent single delivery points (e.g., large postal customers), as well as approximated delivery areas, as of 2023. This should not be taken as an official or definitive placement of ZIP codes in congressional districts, and slight differences in methodology may result in different results.

CRS combined these datasets into a single table using RStudio, then transferred the complete table into a customized Excel workbook file. Some data were cleaned manually in Excel, with spot-checks to validate those transformations. It is possible the workbook contains errors, including potential mistakes that were present in the source datasets. With some exceptions, area and feature names are reproduced in the workbook as they appear in the source dataset.

Updates

This product will be updated as needed in 2024. Any updates will be noted in this space so users are aware when a new version is available to download.

CRS plans to publish a new version of the Congressional District Geography Workbook in 2025 to incorporate any changes to congressional-district boundaries for the 119^th Congress (2025-2026), as well as updates to the source datasets.

Author Information

Ben Leubsdorf Senior Research Librarian

Disclaimer

This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress. Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the United States Government, are not subject to copyright protection in the United

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States. Any CRS Report may be reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you wish to copy or otherwise use copyrighted material.