The Block Boundary Suggestion Project (BBSP) is now in its fourth decade. It began as part of the Census Bureau’s first nationwide Redistricting Data Program for the 1990 Census, following a 1984 pilot test that yielded positive results, which led to its full implementation. While census blocks were first used in 1940, only for cities of 50,000 or more inhabitants and other governments that contracted for the work, they were first used nationwide in 1990. Along with the nationwide census block-numbering system, which gave states the small-area geography they needed to meet Voting Rights Act obligations and minimal-population-deviation districting standards, BBSP helped move redistricting from a paper-based, adding-machine operation toward a computerized, digital process. From the start, participation was voluntary for each state, and the program was organized into sequential phases, a structure that has carried forward since the 1990 Census.
The most consequential changes to BBSP during the 2020 cycle. In the 2010 program, the block-boundary and voting-district work were combined into a single stage, Phase 2, the Voting District/Block Boundary Suggestion Project. For 2020, the Census Bureau separated the two, making the Block Boundary Suggestion Project its own Phase 1 and the Voting District Project Phase 2. The 2020 program also allowed states, for the first time, to review legal boundaries, such as incorporated places and certain county subdivisions, in coordination with the annual Boundary and Annexation Survey, since those legal lines also serve as census tabulation block boundaries. Together, these adjustments set the template for separate phases and a built-in legal-boundary review, which the program still follows.
For 2030, the framework is largely the same as the one set in 2020. The Census Bureau announced the 2030 Redistricting Data Program in the Federal Register on July 9, 2024, and formally commenced Phase 1, the Block Boundary Suggestion Project, on July 30, 2025, again opening it as a voluntary, phased program with the same coordinated legal-boundary review. The Bureau plans to process the suggestions and give state liaisons the opportunity to verify them in early 2027, the same verification step that has anchored recent cycles. The most visible change is the tool: GUPS Web, the Census Bureau’s web-based version of the Geographic Update Partnership Software, which upgrades the desktop-installed application. It was released on February 10, 2026, with BBSP updates due May 29, 2026.
For more information on the program’s structure and current 2030 deadlines, see the Census Bureau’s Redistricting Data Program Management page.
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