The 2020 Census Redistricting Data Program provided states the opportunity to delineate voting districts and to suggest census block boundaries for use in the 2020 Census redistricting data tabulations (Redistricting Data [Public Law 94-171] Summary File). The program is also responsible for the delivery of those tabulations to the states, statutorily required by one year from Census Day. The program ensured continued dialogue with the states in regard to 2020 Census planning, thereby allowing states ample time for their planning, response, and participation. In addition, the Redistricting Data Program periodically collects state legislative and congressional district boundaries, when they are changed by the states through redistricting.

• Phase 1 - Block Boundary Suggestion Project
• Phase 2 - Voting District Project
• Phase 3 - Delivery of the 2020 Census P.L. 94-171 Redistricting Data Files and Geographic Products
• Phase 4 - Collection of Post-2020 Census Redistricting Plans
• Phase 5 - Evaluation of the 2020 Census Redistricting Data Program and Recommendations for 2030

The Block Boundary Suggestion Project (BBSP), Phase 1 of the 2020 Census Redistricting Data Program, provided states the opportunity to submit their suggestions for the 2020 Census tabulation block inventory. Suggestions were made by designating the desirability of linear features for use as 2020 Census tabulation block boundaries. In addition, states had the opportunity to submit suggested legal boundary updates as well as updates to other geographic areas. These actions allowed states to construct some of the small area geography they need for legislative redistricting. Participation in Phase 1 of the Redistricting Data Program was conducted through the non-partisan liaison designated by each state. Phase 1 was conducted in two parts, an initial identification of the updates needed, and a verification stage to ensure the suggested updates were accurately applied.

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The Voting District Project, Phase 2 of the 2020 Census Redistricting Data Program, provided states the opportunity to submit their voting districts (ex. wards, precincts, etc.) for inclusion in the 2020 Census Redistricting Data tabulations (P.L. 94-171 Redistricting Data). In addition, states had the opportunity to submit suggested legal boundary updates as well as updates to other geographic areas. These actions allowed states to construct some of the small area geography they needed for legislative redistricting. Participation in Phase 2 of the Redistricting Data Program was conducted through the non-partisan liaison designated by each state. Phase 2 was conducted in three cycles. The first two cycles were an initial identification of the voting districts and a verification stage to ensure the suggested updates were accurately applied. The third cycle was an additional round of verification, for those states participating in the first two stages, to further review and adjust the voting districts.

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For Phase 3 – Data Delivery, the Director of the Census Bureau, in accordance with 13 U.S.C. 141(c), furnished the Governor and state legislative leaders, both the majority and minority, with 2020 Census population counts for standard census tabulation areas (e.g., state, Congressional district, state legislative district, American Indian area, county, city, town, census tract, census block group, and census block) regardless of a state’s participation in Phase 1 or 2. In addition, for those states participating in Phase 2, standard census tabulation were provided for voting districts.

As a lesson learned from past decennial censuses, it was vital that the Census Bureau produce a prototype product to illustrate what the states should expect from the decennial census. This prototype was used to build and test systems in advance of the official data release so that states could begin work immediately, as many have short statutory deadlines that begin with the receipt of their data. In 2019, we used the prototype data product to illustrate and solicit feedback on what the 2020 Census P.L. 94-171 Redistricting Data File would look like and how it addressed the needs of the states for their legislative redistricting requirements.

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After receipt of the official redistricting data, the 50 states, the District of Columbia (DC), and the Commonwealth of Puerto Rico (PR) began redrawing and adopting their post-2020 Census congressional and legislative district plans. During Phase 4, the Redistricting Data Program invites the 50 states, DC, and PR to provide those newly adopted congressional and legislative district plans to the Census Bureau.

Phase 4 is conducted in two cycles, the initial delineation cycle and the verification cycle. During initial delineation, states have the opportunity to provide their newly adopted plans to the Census Bureau. The Census Bureau loads the newly adopted plans into our geographic database, extracts the newly adopted plans from the geographic database, and sends the redistricting plans back to the states for a final verification. During verification, the states have the opportunity to review, provide feedback, and approve the redistricting plans as reflected in our geographic database. Once the plans are approved by the states, the Census Bureau will use these new boundaries in upcoming data products from both the 2020 Census and the American Community Survey (ACS). This process is repeated for each congressional session, collecting any congressional or legislative boundary changes that have occurred since the previous collection.

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For more information regarding the 2020 Redistricting Data Program, please:

• Call the Redistricting Data Program staff at (301) 763-4039.
• Refer to the Federal Register Notice, Establishment of the 2020 Census Redistricting Data Program.
• Or read Designing P.L. 94-171 Redistricting Data for the Year 2020 Census - The View From the States, the evaluation of the 2010 Census Redistricting Data Program and the recommendations from the States for the 2020 Census Redistricting Data Program