Local governments generally include two tiers: counties, also known as boroughs in Alaska and parishes in Louisiana, and municipalities, or cities/towns. In some States, counties are divided into townships. Municipalities can be structured in many ways, as defined by State constitutions, and are called, variously, townships, villages, boroughs, cities, or towns. Various kinds of districts also provide functions in local government outside county or municipal boundaries, such as school districts or fire protection districts.

Municipal governments—those defined as cities, towns, boroughs (except in Alaska), villages, and townships—are generally organized around a population center and in most cases correspond to the geographical designations used by the United States Census Bureau for reporting of housing and population statistics. Municipalities vary greatly in size, from the millions of residents of New York City and Los Angeles to the few hundred people who live in Jenkins, Minnesota.

Municipalities generally take responsibility for parks and recreation services, police and fire departments, housing services, emergency medical services, municipal courts, transportation services (including public transportation), and public works (streets, sewers, snow removal, signage, and so forth).

Whereas the Federal Government and State governments share power in countless ways, a local government must be granted power by the State. In general, mayors, city councils, and other governing bodies are directly elected by the people.