The Census Bureau uses a variety of geographic codes to describe different characteristics of the geographic entity or feature. We use geographic codes for sorting names for presentation purposes, describing the relationship between geographies (such as the relationships between some county subdivisions and places), identifying if an area is a legally or statistically defined entity, and describing the classification category of the entity or feature. The types of codes are further described below. These codes can be found in many of our geographic products including the TIGER/Line Shapefiles and Gazetteer files.
The Understanding Geographic Identifiers page includes a discussion of what geographic identifiers are, how they are formed and what they are used for. This page also includes details on the differences between FIPS and GNIS codes.
The American National Standards Institute (ANSI) codes are standardized numeric or alphabetic codes issued by the American National Standards Institute (ANSI) to ensure uniform identification of geographic entities through all federal government agencies. The codes on this webpage include the Federal Information Processing Series (FIPS) codes, Geographic Names Information System (GNIS) Identifiers, and Census Bureau issued codes for geographic entities. Entities covered by these codes are American Indian Areas, congressional districts, counties, county subdivisions, metropolitan and micropolitan statistical areas, places, school districts, states, and voting districts.
The 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.
The functional status codes describe 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.
The legal/statistical area description (LSAD) codes describe 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 MAF/TIGER Feature Class Codes (MTFCCs) are 5-digit codes assigned by the Census Bureau intended to classify and describe geographic objects or features.
The Route Type Code describes the type of road.