The Census Bureau updates its inventory of MCDs based on results of the BAS, its periodic survey of all counties, along with specified MCDs and incorporated places. In each year from 1981 through 1987, county officials (and, occasionally, State or regional officials) provided information to the Census Bureau about correct names, legal (or governmental) descriptions, and legal boundaries of MCDs. In 1988 and 1990, the BAS obtained this information directly from the officials of MCDs that had actively functioning governments. Where the MCDs were administrative subdivisions rather than functioning local governments, the BAS asked that county officials provide this information.
The BAS mailout to local governments includes maps showing the latest boundaries in the Census Bureau’s digital geographic data base, the Topologically Integrated Geographic Encoding and Referencing (TIGER) data base. The Census Bureau uses the information that the local officials provide to update its files for the decennial census; these BAS responses also are used to prepare for the population estimates program, the Census of Governments, and other surveys and programs.
The name of an MCD is its unique legal identifier; the legal (or governmental) area description, also called legal status, of an MCD is a generic category dictated by State law regarding subcounty units. It is the specific term that describes the type of MCD, such as town, township, magisterial district, and election precinct. On a nationwide basis, these terms are descriptive and not functional. (Town in one State may mean something different in another State.) In census data tables, the name of the MCD usually precedes its legal description, as in Smith township. Exceptions may occur, as in Township 6, Maguffin, where Township is the legal description of the MCD and the number 6 and Maguffin constitute portions of the name. The BAS includes a form showing the Census Bureau’s most current information on the name and legal description for
