Upload your own maps to see them visualized on Redistricter. Once you've uploaded your maps you can share them through the URL.
All the files necessary for custom map uploads can be downloaded through the redistricting application Daves Redistricting. Once your Daves Redistricting map is ready to export to Redistricter, select export then choose the .GeoJSON format. CSV files for the 2020 and 2016 presidential elections can be gathered by selecting the relevant election under the settings tab, then going to the statistics view and downloading the data. Once you have the files downloaded, you can upload them here.
If you want other's people maps you can browse the library of uploaded maps.