A census of governments is taken at five-year intervals as required by law under Title 13, U.S. Code, Section 161. The 2017 Census of Governments (CoG), similar to those taken since 1957, covers three major components – government organization, public employment, and public finances.

Below the state-level, the U.S. Census Bureau’s classification of government units recognizes five basic types of local governments: county, municipal, township, school district, and special-purpose district governments. Municipalities and townships are considered subcounty general-purpose local governments, whereas school district and special district local governments are considered special-purpose local governments.

Data tables for the 2017 Census of Governments (Organization)–along with historical data going back to 1942–are available from the Census Bureau:
https://www.census.gov/data/tables/2017/econ/gus/2017-governments.html

Public use files (list of governments with reference information) along with the Governments Unit Survey methodology (1997-2017) are also available from the Census Bureau: https://www.census.gov/programs-surveys/gus/data/datasets.html

The Individual State Descriptions report prepared by the U.S. Census Bureau provides information about the organization of state and local governments. There is a separate summary for each state and the District of Columbia. The summaries are divided according to the five basic types of local governments recognized for the U.S. Census Bureau’s classification of government units – county, municipal, township, school district, and special district governments.