State legislative districts (SLDs) are the areas from which members are elected to state legislatures. The SLDs embody the upper (senate) and lower (house) chambers of the state legislature. (Nebraska has a unicameral legislature that the U.S. Census Bureau treats as an upper-chamber legislative area for purposes of data presentation. There are, therefore, no data by lower chamber.)
It is possible to have SLDs that cover only part of a state. In such instances, any areas for which SLDs are not defined are coded "ZZZ" and treated as a single SLD for purposes of data presentation. A unique census code of up to three characters, identified by state participants, is assigned to each SLD within state.