These Block Equivalency Files (BEFs) are the whole 2020 Census tabulation block representations of the 2026 State Legislative District plans as submitted by the states to the U.S. Census Bureau. The .ZIP file contains a national block equivalency file and individual state files for two states that had changes to both their state legislative districts - upper chamber and lower chamber plans (Minnesota and Mississippi) and one state with changes only to their state legislative districts - upper chamber plans (Michigan). The fields in these files should be imported as text to preserve leading zeros. 

In instances where plans included split 2020 Census tabulation blocks, the Census Bureau requested that the state assign the whole block to one district for the purpose of tabulating data. These block equivalency files contain the whole block tabulation plan.

Four states split blocks or continued to split blocks in their 2026 State Legislative District- Upper Chamber (SLDU) and State Legislative District- Lower Chamber (SLDL) plans: Colorado, Minnesota, North Dakota, and Washington. Additionally, Delaware continued to split a block in their 2026 SLDU plan and Pennsylvania continued to split a block in their 2026 SLDL plan.

• The block equivalency files are based on the original 2020 Census tabulation blocks as they appeared in the official 2020 Census Data Products. If you are working with geographic data created after the 2020 Census—such as shapefiles, GeoDatabases, or online viewers like TIGERWeb—you may notice slight differences between the blocks shown in these products and those from the original 2020 Census products (and used to create these BEFs). These differences occur when block boundaries are updated after 2020 for greater spatial accuracy. For example, if a block boundary follows a road or the edge of an incorporated place, and that road or boundary is adjusted to better match real-world features, the block boundary will change as well. The blocks released with the 2020 Census reflect their original shapes, and jurisdictions their 2020 boundaries, while blocks and jurisdictions in post-2020 products (also known as “current blocks” or "current geography") show any updates made since then.
• A unique 3-character census code, identified by state participants, is assigned to each state legislative district upper chamber (SLDU) and lower chamber (SLDL) within the state. In Connecticut, Illinois, Massachusetts, Louisiana, New Hampshire, Wisconsin, and Puerto Rico, the state did not assign the current state legislative districts to cover all of the state or equivalent area. The code “ZZZ” has been assigned to areas with no state legislative districts defined (usually large water bodies). These unassigned areas are treated within the state as a single state legislative district for purposes of data presentation.
• Nebraska has a unicameral legislature and the District of Columbia has a single council, both of which the Census Bureau treats as upper‐chamber legislative areas (SLDUs) for the purpose of data presentation. Therefore, there are no data by the lower chamber of the state legislative districts (SLDLs) for either Nebraska or the District of Columbia.
• The state of New Hampshire uses floterial districts in their lower-chamber (SLDL) plan. Floterial districts are overlay districts made up of two or more discrete districts. These discrete or component districts are those represented in the New Hampshire SLDL TIGER/Line shapefile. A listing of the floterial districts and their component districts is available as a PDF and as a comma delimited text file.