In most of the United States, counties are the political subdivisions of a state. The city, town, or populated place that houses county government is known as the seat of its respective county. Generally, the county legislature, county courthouse, sheriff's department headquarters, hall of records, jail and correctional facility are located in the county seat, though some functions may also be located or conducted in other parts of the county, especially if it is geographically large. A county seat is usually, but not always, an incorporated municipality. The exceptions include the county seats of counties that have no incorporated municipalities within their borders, such as Arlington County, Virginia. Ellicott City, the county seat of Howard County, is the largest unincorporated county seat in the United States, followed by Towson, the county seat of Baltimore County, Maryland. Likewise, some county seats may not be incorporated in their own right, but are located within incorporated municipalities. For example, Cape May Court House, New Jersey, though unincorporated, is a section of Middle Township, an incorporated municipality. In some of the colonial states, county seats include or formerly included "Court House" as part of their name,.
In New England, the town, not the county, is the primary division of local government. Historically, counties in this region have served mainly as dividing lines for the states' judicial systems. Connecticut and Rhode Island have no county level of government and thus no county seats, and Massachusetts has dissolved many but not all of its county governments. In Vermont, Massachusetts, and Maine the county seats are legally designated shire towns. County government consists only of a Superior Court and Sheriff, both located in the respective shire town. Bennington County has two shire towns, but the Sheriff is located in Bennington.
In Virginia, a county seat may be an independent city surrounded by, but not part of, the county of which it is the administrative center; for example, Fairfax City is both the county seat of Fairfax County and completely surrounded by Fairfax County, but the city is politically independent of the county.
Two counties in South Dakota have their county seat and government services centered in a neighboring county. Their county-level services are provided by Fall River County and Tripp County, respectively.
In Louisiana, which is divided into parishes rather than counties, county seats are referred to as parish seats.
Alaska
is divided into boroughs rather than counties; the county seat in these case is referred to as the "borough seat"; this includes six consolidated city-borough governments. The Unorganized Borough, which covers 49% of Alaska's area, has no county seat or equivalent.
Lists of U.S. county seats by state
The state with the most counties is Texas, with 254, and the state with the fewest counties is Delaware, with 3.
