README for “Congressional Districts 1995-Present” dataset. U.S. Department of Commerce (DOC), United States Census Bureau (USCB); U.S. Department of Transportation (USDOT), Bureau of Transportation Statistics (BTS) [distributor] 2025-05-29 ---------------------------------------------------------------- LINKS TO DATASET ---------------------------------------------------------------- A. Dataset archive link: https://doi.org/10.21949/1520799 B. NTAD catalog dataset link (Current Year): https://doi.org/10.21949/1522027 ---------------------------------------------------------------- SUMMARY OF DATASET ---------------------------------------------------------------- The Congressional Districts 1995-Present dataset is from the United States Census Bureau (USCB), and is part of the U.S. Department of Transportation (USDOT)/Bureau of Transportation Statistics’s (BTS's) National Transportation Atlas Database (NTAD). The TIGER/Line shapefiles and related database files (.dbf) are an extract of selected geographic and cartographic information from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). The MTDB represents a seamless national file with no overlaps or gaps between parts, however, each TIGER/Line shapefile is designed to stand alone as an independent data set, or they can be combined to cover the entire nation. Congressional districts are the 435 areas from which people are elected to the U.S. House of Representatives. This dataset also includes 9 geographies for non-voting at large delegate districts, resident commissioner districts, and congressional districts that are not defined. After the apportionment of congressional seats among the states based on census population counts, each state is responsible for establishing congressional districts for the purpose of electing representatives. Each congressional district is to be as equal in population to all other congressional districts in a state as practicable. In Connecticut, Illinois, and New Hampshire, the Redistricting Data Program (RDP) participant did not define the CDs to cover all of the state or state equivalent area. In these areas with no CDs defined, the code "ZZ" has been assigned, which is treated as a single CD for purposes of data presentation. The TIGER/Line shapefiles for the District of Columbia, Puerto Rico, and the Island Areas (American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, and the U.S. Virgin Islands) each contain a single record for the non-voting delegate district in these areas. ---------------------------------------------------------------- TABLE OF CONTENTS ---------------------------------------------------------------- A. General Information B. Sharing/Access & Policies Information C. Data and Related File Overview D. Methodological Information E. Data-Specific Information for: Congressional Districts 1995-Present [datasets] F. Update Log ---------------------------------------------------------------- A. GENERAL INFORMATION ---------------------------------------------------------------- 0. Title of Dataset: Congressional Districts 1995-Present [dataset] 1. Description of Dataset: The Congressional Districts 1995-Present dataset is from the United States Census Bureau (USCB), and is part of the U.S. Department of Transportation (USDOT)/Bureau of Transportation Statistics’ (BTS's) National Transportation Atlas Database (NTAD). The TIGER/Line shapefiles and related database files (.dbf) are an extract of selected geographic and cartographic information from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). The MTDB represents a seamless national file with no overlaps or gaps between parts, however, each TIGER/Line shapefile is designed to stand alone as an independent data set, or they can be combined to cover the entire nation. Congressional districts are the 435 areas from which people are elected to the U.S. House of Representatives. This dataset also includes 9 geographies for non-voting at large delegate districts, resident commissioner districts, and congressional districts that are not defined. After the apportionment of congressional seats among the states based on census population counts, each state is responsible for establishing congressional districts for the purpose of electing representatives. Each congressional district is to be as equal in population to all other congressional districts in a state as practicable. In Connecticut, Illinois, and New Hampshire, the Redistricting Data Program (RDP) participant did not define the CDs to cover all of the state or state equivalent area. In these areas with no CDs defined, the code "ZZ" has been assigned, which is treated as a single CD for purposes of data presentation. The TIGER/Line shapefiles for the District of Columbia, Puerto Rico, and the Island Areas (American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, and the U.S. Virgin Islands) each contain a single record for the non-voting delegate district in these areas. 2. Dataset archive link: https://doi.org/10.21949/1520799 3. Authorship Information: Principal Data Creator or Data Manager Contact Information Institution: U.S. Department of Commerce (DOC), United States Census Bureau (USCB) Address: 4600 Silver Hill Rd., Washington D.C. 20233 Contact: geo.bas@census.gov/ geo.geography@census.gov Data Distributor Contact Information Name: National Transportation Atlas Database (NTAD) Institution: U.S. Department of Transportation (USDOT), Bureau of Transportation Statistics (BTS), Office of Spatial Analysis and Visualization (OSAV) Address: 1200 New Jersey Ave. SE, Washington D.C. 20590 Email: ntad@dot.gov 4. Date of data collection and update interval: This dataset is updated annually. 5. Geographic location of data collection: United States of America 6. Information about funding sources that supported the collection of the data: United States Census Bureau (USCB), U.S. Department of Commerce (DOC) ---------------------------------------------------------------- B. SHARING/ACCESS & POLICIES INFORMATION ---------------------------------------------------------------- 0. Recommended citation for the data: U.S. Department of Commerce (DOC), United States Census Bureau (USCB), U.S. Department of Transportation, Bureau of Transportation Statistics (BTS) [distributor]. Congressional Districts 1995-Present [datasets]. https://doi.org/10.21949/1520799 1. Licenses/restrictions placed on the data: These data are in the Public Domain. 2. Was data derived from another source?: No. 3.This document was created to meet the requirements enumerated in the U.S. Department of Transportation's 'Plan to Increase Public Access to the Results of Federally-Funded Scientific Research' Version 1.1 << https://doi.org/10.21949/1520559 >> and guidelines suggested by the DOT Public Access website << https://doi.org/10.21949/1503647 >>, in effect and current as of December 03, 2020. ---------------------------------------------------------------- C. DATA & RELATED FILE OVERVIEW ---------------------------------------------------------------- 1. File List for the Congressional Districts 1995-Present dataset A. Filename: Congressional_Districts_NTAD1995_Present.zip Short description: Compressed file folders containing the geospatial data for Congressional Districts 1995-Present dataset. File folders are classified by NTAD publication year and data vintage year or date respectively. B. Filename: bts_NTAD_Congressional_Districts_DMP_20250529.pdf Short description: A PDF file containing the Data Management Plan that was created for current and future management of the data and associated files. C. Filename: bts_NTAD_Congressional_Districts_README_20250529.txt Short description: The README.txt file that includes human-readable information about the data, variable definitions, contact information, and other contextual information. The file you are reading now. 2. File List for the Congressional_Districts_NTAD1995_Present.zip collection. A. Filename: NTADXXXX_SHP_Final_Congressional_Districts_XXX_XXXX.zip, NTADXXXX_SHP_Final_Congressional_Districts_XXXX_XX_XX.zip or NTADXXXX_GDB_Final_Congressional_Districts_XXXX_XX_XX.zip Short description: Compressed file folders containing the geospatial data for Congressional Districts 1995-Present dataset. Shapefile folders are classified first by NTAD publication year, second by congressional number, and third data vintage year respectively. Shapefile and geodatabase folders after 2018 do not specify congressional number. 3a. File List for the NTADXXXX_SHP_Final_Congressional_Districts_XXX_XXXX.zip and NTADXXXX_SHP_Final_Congressional_Districts_XXXX_XX_XX.zip collections. A. Filename: CDXXX_XXXX.shp or cd.shp Short description: A shapefile containing the geospatial data for Congressional Districts 1995-Present dataset. This includes associated files with extensions .prj, .dbf, .sbn, .sbx, .shx. A portion of files are classified by congressional number and data vintage year respectively. B. Filename: CDXXX_XXXX.txt, CDXXX_XXXX.htm, and CDXXX_XXXX.shp.xml or cd.txt, cd.htm, and cd.shp.xml Short description: Text files containing key metadata and documentation information such as methodology, procedures, data dictionary, etc. A portion of files are classified by congressional number and data vintage year respectively. 3b. File List for the NTADXXXX_GDB_Final_Congressional_Districts_XXXX_XX_XX.zip collection A. Filename: NTADXXXX_GDB_Final_Congressional_Districts_XXXX_XX_XX.gdb.zip Short description: A file geodatabase containing the geospatial data for Congressional Districts 1995-Present dataset. Geodatabase (GDB) folders contain all the necessary components to view and otherwise interact with their data. B. Filename: Congressional_Districts.xml Short description: Text files containing key metadata and documentation information such as methodology, procedures, etc. C. Filename: Congressional_Districts.xlsx Short description: Excel spreadsheet containing the dataset's data dictionary. ---------------------------------------------------------------- D. METHODOLOGICAL INFORMATION ---------------------------------------------------------------- 1. Description of methods used for collection/generation of data: Congressional District TIGER/Line Shapefiles are extracted and downloaded from the Census MAF/TIGER database at a national scale from https://www.census.gov/geographies/mapping-files/time-series/geo/tiger-line-file.html. Information for each member of Congress is appended to the Census Congressional District shapefile using information from the Office of the Clerk, U.S. House of Representatives' website https://clerk.house.gov/xml/lists/MemberData.xml and its corresponding XML file. 2. Instrument- or software-specific information needed to interpret the data: The data and documentation files can be opened with Esri ArcMap and any GIS software package. ---------------------------------------------------------------- E. DATA-SPECIFIC INFORMATION ---------------------------------------------------------------- 1. Congressional Districts data table This dataset is updated annually. Dataset Manager is contacted to verify changes to data resulting in NTAD update. The metadata is updated in the same manner. For the most recent data, please visit the NTAD catalog at https://doi.org/10.21949/1522027 A. Number of variables (columns): The data dictionary found in (PDF documentation) provides definitions for the variables B. Data Dictionary/Variable List: Because of the large number of variables, please refer to the Data Dictionary found within the file Congressional_Districts.txt for names, definitions, and formats of variables. C. Missing data codes: None ---------------------------------------------------------------- F. UPDATE LOG ---------------------------------------------------------------- This bts_Congressional_Districts_20250529_README.txt file was originally created on 2021-03-18 by Dominic Menegus, Geographer, dominic.menegus@dot.gov [Note changes or update to the readme.txt file, e.g.:] 2021-03-18: Original file created 2025-05-29: Revised document, including data descriptions and file organization.