The Census Bureau collects and maintains information describing selected attributes and characteristics of geographic areas. These attributes are Federal Information Processing Series (FIPS) class code, functional status, legal/statistical area description, internal point, and name of geographic entities.
FIPS class codes describe the general characteristics of a geographic area related to its legal or statistical status, governmental status, and in some cases relationship to other geographic entities. Class codes exist for counties; county subdivisions; subminor civil divisions; places; consolidated cities; Alaska Native Regional Corporations; American Indian, Alaska Native, and Native Hawaiian areas; and American Indian tribal subdivisions.
Functional status describes whether a geographic entity is a functioning governmental unit, has an inactive government, is an administrative area without a functioning government, or is a statistical area identified and defined solely for tabulation and presentation of statistical data. Functional status codes are:
|A||Active government providing primary general-purpose functions.|
|B||Active government that is partially consolidated with another government but with separate officials providing primary general-purpose functions.|
|C||Active government consolidated with another government with a single set of officials.|
|E||Active government providing special-purpose functions.|
|F||Fictitious entity created to fill the Census Bureau's geographic hierarchy.|
|G||Active government that is subordinate to another unit of government and thus, not considered a functioning government.|
|I||Inactive governmental unit that has the power to provide primary special-purpose functions.|
|N||Nonfunctioning legal entity.|
Internal point—The Census Bureau calculates an internal point (latitude and longitude coordinates) for each geographic entity. For many geographic entities, the internal point is at or near the geographic center of the entity. For some irregularly shaped entities (such as those shaped like a crescent), the calculated geographic center may be located outside the boundaries of the entity. In such instances, the internal point is identified as a point inside the entity boundaries nearest to the calculated geographic center and, if possible, within a land polygon.
Legal/statistical area description (LSAD)—The LSAD describes the particular typology for each geographic entity; that is, whether the entity is a borough, city, county, town, or township, among others. For legal entities, the LSAD reflects the term that appears in legal documentation pertaining to the entity, such as a treaty, charter, legislation, resolution, or ordinance. For statistical entities, the LSAD is the term assigned by the Census Bureau or other agency defining the entity. The LSAD code is a two-character field that corresponds to a description of the legal or statistical type of entity and identifies whether the LSAD term should be capitalized and should precede or follow the name of the geographic entity. Note that the same LSAD code is assigned to entities at different levels of the geographic hierarchy when they share the same LSAD. For example, the Census Bureau assigns the same LSAD code ("21") to boroughs in New York and Connecticut, although they are county subdivisions in the former and incorporated places in the latter.
Name—Each geographic entity included in Census Bureau products has a name. For most geographic entities, the name is derived from the official legally recognized name, is assigned by local officials participating in Census Bureau statistical area programs, or is based on component entities and determined according to specified criteria. For legal entities, the name appearing in Census Bureau products may be the more commonly used name rather than the name as it appears in legal documents. For example, "Virginia" instead of "the Commonwealth of Virginia"; "Baltimore" instead of "City of Baltimore." In some instances, the name for an entity in Census Bureau products will reflect the official name as well as a more commonly used name listed parenthetically; i.e., San Buenaventura (Ventura), CA, or Bath (Berkeley Springs), WV. For some types of geographic entities, the name reflected in Census Bureau products may be the geographic entity code assigned by local officials. For example, a census tract's name is the actual number assigned by local officials, such as 1.01, whereas the census tract code would reflect a full four-digit base code and two-digit suffix (for example, for the preceding tract named 1.01, 000101).