Districtr
This mapping tool lets you draw and share redistricting plans as well as draw and describe your “community of interest.” Districtr has been used by tens of thousands of people and was adopted as the official public mapping platform in big cities like New York and Los Angeles all the way down to tiny Grand County, Utah. Draw a map, explain why your community should stay together, and share your vision of fair representation.
You can start drawing maps at districtr.org, or you can test out a newly updated version 2 at beta.districtr.org.