MCDs, UTs, and CCDs within each State. The FIPS 55 class codes most commonly used to identify county subdivisions are the following:
- T1 (governmentally active MCD not coextensive with an incorporated place)
- Z1 (governmentally inactive or nonfunctioning MCD)
- Z3 (unorganized territory)
- Z5 (CCD or CSA)
For its censuses from 1960 to 1990, the Census Bureau established a series of MCD/CCD codes to identify and alphabetize all county subdivisions within each county. These are three-digit numeric identifiers, usually gapped at intervals of five (such as 005, 010, 015) that serve to organize the county subdivision names alphabetically. To identify any county subdivision, it is necessary to use not only its MCD/CCD code, but also the State code and the county code. Because the MCD code is unique only within county (for instance, the code 005 generally is repeated in every county), it is necessary to use State and county codes as well to uniquely identify MCDs/CCDs on a nationwide basis. The Census Bureau published both census and FIPS codes for all entities appearing in its 1990 data products. For the year 2000, however, the FIPS codes—State, county, locality, and Alaska Native/American Indian area—will be the only geocodes used in census data products.
The Census Bureau treats incorporated places as either dependent on, or independent of, the MCDs in which they are located. (All CDPs are considered dependent on the county subdivision in which they are located, and all places are dependent on CCDs.) In the hierarchical data tables, dependent places are indented under the name of the MCD/CCD in which they are located, and the count for each dependent place is included in that MCD/CCD total. In some MCD States, all incorporated places are independent; in others, all incorporated places are dependent. Still other MCD States contain both independent and dependent places. Figures 8-2 and 8-3 illustrate how the Census Bureau treats a dependent and an independent incorporated place in its data presentations. Table 8-4 identifies the legal relationship of each State’s incorporated places, whether they are dependent on, or independent of, their county subdivisions.
