DistrictBuilder is an open-source software application developed by the Public Mapping Project that allows users to draw experimental redistricting maps for 25 states. ¹ The software allows users to draw redistricting plans for state legislatures, Congressional districts, and local jurisdictions.  ²

The platform lets users create and edit district plans and display demographics and election data. ³ DistrictBuilder says its software provides the same block-level data used in official redistricting plans.  ⁴

Background

DistrictBuilder is a free, open-source, online software developed by the Public Mapping Project in partnership with Azavea, a software development firm. ⁴

District Builder supports map creation for 25 states. ¹ It gives the public an easy-to-use online mapping tool to draw legislative maps so that citizens have access to the same information that legislators have in drawing congressional maps. ²

DistrictBuilder says it puts the power of drawing electoral maps in the hands of the people to make redistricting a transparent process and prevent gerrymandering. ⁴ The app touts the maps as being drawn “rapidly.”  ⁴

Donors

The Alfred P. Sloan Foundation donated $1.2 million to the Public Mapping Project specifically to support the District Builder app, as well as to support more data collection to prepare for the 2020 redistricting cycle. ⁵

Other donors including the Joyce Foundation, Amazon in Education, the Judy Ford Wason Center for Public Policy at Christopher Newport University, and pro-bono work by Azavea for the software development.  ⁶

Practical Use

DistricBuilder has an organization page for groups of concerned citizens, nonprofits, or redistricting commissions to use to create their own community.  ⁴ Users have access to district statistics on population, race and ethnicity, election results, contiguity, and compactness. ⁷

The map templates follow the commonly accepted redistricting criteria guide of the National Conference of State Legislatures. ⁸ The map templates ensure contiguity, which means all parts of the district must be accessible to each other in a single, unbroken shape. ⁸

The maps drawn by the software can be exported for users to share with lawmakers, embed in an article, or share on social media.  ⁴

The software can also create majority-minority districts that comply with the 1965 Voting Rights Act and court precedents.  ⁸

Founding

DistrictBuilder was developed in 2010 by University of Florida political science professor Michael P. McDonald and Massachusetts Institute of Technology social scientist Micah Altman. ⁹

In 2010, the two launched public redistricting efforts in 10 states by working through student competitions or through partnering with organizations such as Common Cause and League of Women Voters.  ⁹

In 2010, the project had to set up 10 different websites for each state. After the 2020 Census, it was able to accommodate 10 states on a single DistrictBuilder platform.  ⁹

Impact

Micah Altman, co-founder of DistrictBuilder, said in states with independent redistricting commissions, or states where the maps were redrawn after litigation, such maps looked like some of the maps proposed through the DistrictBuilder platform.  ⁹

In 2018, Draw the Lines PA held 20 events around Pennsylvania in opposition to gerrymandering. The group encouraged state residents to use the DistrictBuilder tool and then share their maps with lawmakers. ¹⁰

Residents in Minneapolis, Minnesota used DistrictBuilder in 2013 to submit maps to the city for districts in city council elections. Thise led to creating two new voting districts, and to electing the first Hispanic and the first Somali American to the city council. ¹¹

In 2021, Dane County, Wisconsin, a jurisdiction that includes the state capital Madison, began using DistrictBuilder as its official tool for public submissions on redistricting. ¹¹

1. “Mapping Software for Redistricting.” Protecting Native American Voting Rights. Accessed December 8, 2025. https://vote.narf.org/redistricting/mapping-software/ 
2. Press Release. “Public Mapping Project wins 2018 Brown Democracy Medal.” PennState. April 16, 2018. Accessed December 5, 2025. https://www.psu.edu/news/impact/story/public-mapping-project-wins-2018-brown-democracy-medal 
3. Press Release. “MIT Libraries’ research contributes to award-winning redistricting software, DistrictBuilder.” Massachusetts Institute on Technology. November 5, 2012. Accessed December 9, 2025. https://news.mit.edu/2012/mit-libraries-research-contributes-to-award-winning-redistricting-software-districtbuilder 
4. DistrictBuilder. Accessed December 8, 2025. https://www.districtbuilder.org/ 
5. Public Mapping Project. Accessed December 5, 2025. https://www.publicmapping.org/ 
6. “Redistricting.” U.S. Elections Project. Accessed December 8, 2025. https://www.electproject.org/redistricting 
7. “Mapping Tools.” District Builder 2.0. Accessed December 8, 2025. https://redistrictingdatahub.org/tools/choose-your-own-mapping-tool/mapping-tools/ 
8. McGlone, Daniel. “Draw fair districts for every state with our free redistricting tool. Check it out at.” Medium. September 7, 2021. Accessed December 8, 2025.https://medium.com/districtbuilder/tutorial-how-to-evaluate-your-map-583ccc0b6b69 
9. Bliss, Laura. “MapLab: New Map Tools Make Redistricting More Accessible.” Bloomberg. September 22, 2021. Accessed December 9, 2025. https://www.bloomberg.com/news/newsletters/2021-09-22/maplab-map-tools-expand-public-participation-in-redistricting 
10. Press Release. “Draw the Lines Project Launch.” September 17, 2018. Accessed December 9, 2025. https://seventy.org/press-testimony/draw-the-lines-project-launch 
11. Hernandez, Kristian. “DIY Redistricting Allows Public to Draw Maps in More States.” Stateline. August 31, 2021. Accessed December 11, 2025. https://stateline.org/2021/08/31/diy-redistricting-allows-public-to-draw-maps-in-more-states/