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Block Boundary Suggestion Project (BBSP)

Redistricting Data Program Phase 1

Program webpage
Census email contact:  rdo@census.gov

What is BBSP?

The Block Boundary Suggestion Project (BBSP) is a chance to preview the census enumeration blocks that will be used for the 2030 Census and to make suggestions for new boundaries that can be used in state and local redistricting.

It is also an opportunity to fix problematic census tabulations blocks and to create new blocks that can be used for other purposes like transportation planning or for tabulating other non-political boundaries.

Why does BBSP matter to a community?

A community’s voting precincts, commission districts, and legislative districts are built using whole census blocks. Any block boundary that is not present in the P.L. 94-171 Redistricting Data, that the Census Bureau will release in early 2031, cannot be used for redistricting or for voting precincts.

BBSP can also be used to maintain other important, non-standard block boundaries from the 2020 Census (power lines, streams, property lines, ridgetops, etc.) in next decade’s data.

How does BBSP work?

States can propose new non-standard features (e.g., power lines, streams, property lines, ridgetops, etc.) for use as census tabulation block boundaries. They can also suggest the removal of non-standard boundaries from the 2020 data that the Census Bureau proposes to retain or to request retention of block boundaries that are proposed to be removed.

Each state’s officially designated liaison is responsible for submitting changes to the Census Bureau. They work with local officials such as election supervisors and planners to complete the review.

Who can participate in BBSP?

The Tennessee Comptroller of the Treasury is the state’s redistricting liaison and oversees BBSP for the State of Tennessee. They will contact county officials, including planners and election administrators, about participation in the program. They will also hold meetings at regional offices around the state with interested counties.

For questions please contact

Matthew Hill
GIS Supervisor
Tennessee Comptroller of the Treasury
(615) 401.7828
Matthew.Hill@cot.tn.gov

What software and data are required?

The Census Bureau provides the necessary software and data to participate in the program. This includes an online platform called the Geographic Update Partnership Software (GUPS) that is used to make changes. Advanced geographic information systems users may elect to use their software for the review.

Notices and Census Bureau Announcements

In late 2025, the Census Bureau is expected to publish a Federal Register notice to announce the beginning of the 2030 Block Boundary Suggestion Project (BBSP).