In the United States, a county or county equivalent is an administrative subdivision of a state or territory, typically with defined geographic boundaries and some level of governmental authority. The term "county" is used in 48 states, while Louisiana and Alaska have functionally equivalent subdivisions called parishes and boroughs, respectively. Counties and other local governments exist as a matter of U.S. state law, so the specific governmental powers of counties may vary widely between the states, with many providing some level of services to civil townships, municipalities, and unincorporated areas. Certain municipalities are in multiple counties. Some municipalities have been consolidated with their county government to form consolidated city-counties or have been legally separated from counties altogether to form independent cities. Conversely, counties in Connecticut and Rhode Island, eight of Massachusetts's 14 counties, and Alaska's Unorganized Borough have no government power, existing only as geographic distinctions.
The United States Census Bureau uses the term "county equivalent" to describe places that are comparable to counties, but called by different names. Louisiana parishes, the organized boroughs of Alaska, independent cities, and the District of Columbia are equivalent to counties for administrative purposes. Alaska's Unorganized Borough is further divided into 11 census areas that are statistically equivalent to counties. In 2024, the U.S. Census Bureau began to also recognize Connecticut's councils of governments, which took over some of the regional powers from the state's former county governments, as county equivalents.