Jeffrey B. Lewis, Brandon DeVine, and Lincoln Pritcher with Kenneth C. Martis
The webpage for this project can be found at http://amypond.sscnet.ucla.edu/districts.
These repositiories provides digital boundary definitions in GeoJson format for every U.S. Congressional District in use between 1789 and 2012. These were produced as part of NSF grant SBE-SES-0241647 between 2009 and 2013.
The current release of these data is experimental. We have had done a good deal of work to validate all of the shapes. However, it is quite likely that some irregulaties remain. Please email [email protected] with questions or suggestions for improvement. We hope to have a ticketing system for bugs and a versioning system up soon. The district definitions currently available should be considered a pre-release version.
Many districts were formed by aggregragating complete county shapes obtained from the National Historical Geographic Information System (NHGIS) project and the Newberry Library's Atlas of Historical County Boundaries. Where Congressional Districts boundaries did not coincide with county boundaries districts shapes were constructed district-by-district using a wide variety of legal and cartographic resources. Detailed descriptions of how particular districts were constructed and the authorities upon which we relied are available (at the moment) by request.
The Principal Investigator on the project was Jeffrey B. Lewis. Brandon DeVine and Lincoln Pitcher researched district definitions and produced thousands of digital district boundaries. The project relied heavily on Kenneth C. Martis' The Historical Atlas of United States Congressional Districts: 1789-1983. (New York: The Free Press, 1982). Martis also provided guidance, advice, and source materials used in the project.
Jeffrey B. Lewis, Brandon DeVine, Lincoln Pitcher, and Kenneth C. Martis. (2013) Digital Boundary Definitions of U.S. Congressional Districts, 1789-2012. [Data file and code book]. Retrieved from http://amypond.sscnet.ucla.edu/districts on [date of download].
If you use the shapes in your research, please send along an email describing your project and giving a citations to resulting to working papers and publications Geographic information
The district definitions are organized by state and the range of Congresses in which they were operative. Each unique district has been given a unique identifier with the following format SSNNBBBEEE where SS is the state fips code, NN is the district number, BBB is the number of first Congress in which that district was used and EEE is the last Congress in which that district was used.
District geographic definitions are encoded in US Census standard unprojected format using the NAD83 coordinate datum (PostGIS SRID 4269). The PROJ.4 string is:
+proj=longlat +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +no_defs Download
The files provide districts shapes for each Congress in ERSI's Shapefile format. The current files are version 1.00 (June 20, 2013).
Our enumeration of Congressional districts in effect in a particular Congress follows Martis. At large districts are numbered "0". In a few cases, shapes describing Indian territories within states during the 18th and early 19th centuries are included in the shape files. These territories are always assigned district number "-1". The Congressional districts in the shape files match districts contained in rollcall voting data files and Congressional roster files available on Keith Poole's Voteview site here and here. There are a very few instances in which there is no member representing a particular district in a particular Congress (a file enumerating all known discrepancies between the Voteview data and these shapes is available here.
Starting with the 103rd Congress, district boundary files are produced by the US Census and we rely on those shapes for Congresses beginning with the 103rd. US Census Tigerline files associated the 1990 Decennial Census were used to construct districts from the 98th to the 102nd Congress (except where noted in the documentation files below). For Congresses between the 1st and the 97th, district boundaries were formed in one of two ways. For districts that were made up of collections of complete counties, historical county boundaries from NHGIS or were dissolved to form district boundaries. Districts that divided one or more counties were formed on a case-by-case basis. Sources relied upon for these districts are described in the documentation files below.
Access to Excel .xlsx files containing references and documentation related to how each district shape was drawn are available at the http://amypond.sscnet.ucla.edu/districts. Access to these files is limited due to possible copyright issues (some of the documentation files include images of maps). To obtain access to these materials for research purposes, please email [email protected]. File names indicate the state and range of Congresses covered by districts described in a particular documentation file. [Click to show available documentation files]
Copyright Jeffrey B. Lewis, 2013.