The U.S. Constitution does not mention the existence of local governments. They are created by the state. A city is a municipal government that is created when a state legislature grants a city charter to a local government. There are several forms of city government: mayor-council, council-manager, and commission. During the first half of the twentieth century Americans moved in large numbers to the cities. Since the 1950s the suburbs around the central cities has expanded. The U.S. Census Bureau has defined a Metropolitan Statistical Area as a central city and its suburbs with a combined population of 50,000 or more.

The county is normally the largest territorial and political subdivision of a state. Elected commissioners or supervisors run county governments. They act as a legislature and also administer and enforce laws. A sheriff, district attorney, coroner, clerk, assessor, and treasurer are all part of the county's government. Counties may be divided into smaller political units, such as towns, townships, or villages. The New England town government is one of the oldest forms of government in the United States,