State legislative districts (SLD) are areas from which members are elected to state or equivalent entity legislatures. State legislative districts embody the upper (senate—SLDU) and lower (house—SLDL) chambers of the state legislatures. 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 for the purpose of data presentation. Therefore, there are no data by the lower house of the state legislative districts for either Nebraska or the District of Columbia.

The Census Bureau requested a copy of the state laws and/or applicable court order(s) for each state from their 2020 Redistricting Data Program state liaison. Additionally, the states were asked to furnish their newly established legislative district boundaries and numbers by means of geographic equivalency files.

The Census Bureau entered this information into its geographic database and produced 2020 Census tabulation block equivalency files that depicted the newly defined legislative district boundaries. Each state liaison was furnished with their file and requested to review, submit corrections and certify the accuracy of the boundaries.