A county seat is a town which is the capital of a county. It is often, but not always, an incorporated municipality. County-wide politics and government are conducted here. The county courthouse and county administration are usually located in the county seat.
Special U.S. circumstances
- In Alaska, the borough is the name used for what would be a county in other states (apart from Louisiana). Three consolidated city-county governments exist—Juneau City and Borough, Sitka City and Borough and Yakutat City and Borough. Also, the state's largest city, Anchorage, is legally the Municipality of Anchorage and is included in no borough, making it an independent city.
- The state of California has one consolidated city-county, San Francisco. The city's board of supervisors govern both aspects, and there is both a city police department and a county sheriff, the latter mostly responsible for operating the county jail (which is located in adjacent San Mateo County).
- Colorado has two consolidated city-counties—Denver and Broomfield.
- In Georgia, three consolidated city-counties exist—Athens, Augusta and Columbus.
- The two largest cities in Kentucky, Louisville and Lexington, are "urban-county governments," Kentucky's legal term for a consolidated city-county arrangement.
- In Louisiana, the parish is the name used for counties. As such, the parish seat would be the equivalent of the county seat. The city of New Orleans is coterminous with, and identical to, Orleans Parish.
- In Maryland, the City of Baltimore generally possesses the same powers and responsibilities as the counties within the state. It is an entity lying geographically within, but separate from, the County of Baltimore, which has its county seat in Towson
- In Kansas, Wyandotte County and the city of Kansas City, Kansas operate as a unified government.
- In Missouri, St. Louis City is separate from St. Louis County and is referred to as a "city not within a county."
- Montana has two consolidated city-counties—Anaconda with Deer Lodge County and Butte with Silver Bow County.
- Nevada's state capital of Carson City has been an independent city since 1969.
- In some New England states, such as Connecticut, parts of Massachusetts, and Rhode Island, counties are only geographic designations and do not have any governmental powers. All government is either done at the state level or at the municipal (town or city) level.
- New York City encompasses five counties, and is the county seat of all five of them: New York County (Manhattan), Kings County (Brooklyn), Bronx County (The Bronx), Richmond County (Staten Island), and Queens County (Queens). Because each borough has a separate main post office (and Queens has four), the county seats of the five boroughs are often stated in terms of those main post offices: New York (Manhattan), Brooklyn, Bronx, Staten Island, and Jamaica (Queens), NY. However, the communities served by those main post offices are all within the city limits of New York.
- In Pennsylvania the city of Philadelphia also has the status of a county.
- In Tennessee, the city of Nashville and Davidson County operate under a unified government. Similar arrangements exist between the City of Lynchburg and Moore County, as well as the City of Hartsville and Trousdale County.
- In Virginia, many county seats are politically not a part of the counties they serve; under Virginia law, all municipalities incorporated as cities are independent cities and are not part of any county. Some of the cities in the Hampton Roads area (Virginia Beach, Chesapeake, Newport News, Hampton, and Suffolk) were formed from an entire county. These cities are no longer county seats, since the counties ceased to exist once the cities were completely formed, but are functionally equivalent to counties.