Overview
Legislative boundary files contain information about the areas represented by certain legislators, and are often referred to as legislative or district maps They can be used as a tool to assess redistricting criteria, a reference to draw new district lines or maps, or as a historical reference for comparing different redistricting cycles. The RDH hosts legislative boundary files from 2010 to 2022, and is rehosting additional boundaries as they are enacted and become available.
What are legislative boundary files?
Legislative boundary files are geospatial data that define the areas which legislators represent. In other words, legislative boundary files contain data regarding the district maps passed or enacted by states. They determine the boundaries of a particular constituency and electorate, and the area in which analysis of election results can be performed. The data hosted on our website are shapefiles, and there are different files for Congressional, upper state legislative districts, and lower state legislative districts.
What are the data used for?
Legislative boundary files can be used to compare existing boundaries or maps to proposed boundaries or maps. Using geographic information systems (GIS) software, they are also used to assess any redistricting criteria. For example, they can be mapped with election results to analyze compliance with the Voting Rights Act (VRA). Lastly, the data are used as a reference in the redistricting map drawing process .
Who collected the data?
Legislative boundary files from 2010 to 2020 are from All About Redistricting and re-hosted on the RDH website for each state. All About Redistricting used official state websites to search for all enacted legislative boundary plans between 2000 and 2020. The RDH collected 2022 boundary shapefiles as they were enacted. Sometimes, districts change during mid-decade redistricting or litigation, and RDH plans to continue collecting these new files as they are made available. All About Redistricting keeps track of litigation between cycles and when remedial plans were used to hold elections. For more information about litigation and remedial plans, check out their website.
Where can the data be found on the Redistricting Data Hub website?
Legislative boundary files for former and newly enacted maps can be downloaded from the RDH on each of the state data pages. They can be found by using the “Filter by Type of Data” dropdown menu and selecting “Legislative Boundaries.”