Precinct Boundary and Election Results Data

Precinct level boundaries and election results are among the most difficult election data in the country to obtain. Some states follow best practices of publishing statewide boundary files in an electronic format that can be easily merged with election results, but many do not. In these states, one must collect data from localities. Some localities, too, publish boundary files in an electronic format that can be easily merged with election results, but many do not. For many localities, predominantly those in rural areas, election officials only provide pictures of precinct maps (if at all), which must be converted into usable electronic formats. Precinct boundaries can change, so this task may need to be repeated across elections.

We - the Voting and Election Science Team composed of folks across the country - are doing the painstaking work of creating statewide electronic precinct maps and merging these GIS data with election results. Our work is supported by the Alfred P. Sloan Foundation and the Washington Post. Our current focus is on the 2016 general election, but we are expanding to other elections. We also focus on statewide elections, but we are expanding to congressional and state legislative offices in some states, which can present new difficulties when district boundaries sometimes split precinct boundaries.

Data

We publicly post the resulting GIS data known as shapefiles on the Harvard Dataverse

Software

Some knowledge of GIS software is necessary to use these files. We recommend a freeware application known as QGIS.