A county seat is an administrative center, or seat of government, for a county or civil parish. The term is primarily used in the United States. In the United Kingdom and Ireland county towns have a similar function.
Counties in the United States function similarly to those in the United Kingdom and Canada, acting as administrative subdivisions of a state. They have no sovereign jurisdiction of their own, although some have authority to enact and enforce municipal ordinances. Counties administer state or provincial law at the local level as part of the decentralization of state/provincial authority. In many U.S. states, state government is further decentralized by dividing counties into civil townships, to provide local government services to residents of the county who do not live in incorporated cities or towns.
A county seat is usually, but not always, an incorporated municipality. The exceptions include, but are not limited to, the county seats of counties that have no incorporated municipalities within their borders, such as Arlington County, Virginia and Howard County, Maryland. (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.) The county courthouse and county administration are usually located in the county seat, but some functions may also be conducted in other parts of the county, especially if it is geographically large.
 U.S. counties with more than one county seat
Most counties have only one county seat. However, some counties in Alabama, Arkansas, Iowa, Kentucky, Massachusetts, Mississippi, Missouri, New Hampshire, and Vermont have two or more county seats, usually located on opposite sides of the county. An example is Harrison County, Mississippi, which lists both Biloxi and Gulfport as county seats. The practice of multiple county seat towns dates from the days when travel was difficult. There have been few efforts to eliminate the two-seat arrangement, since a county seat is a source of pride (and jobs) for the towns involved.
There are 34 counties with multiple county seats (no more than two each) in 9 states:
- Coffee County, Alabama
- St. Clair County, Alabama
- Arkansas County, Arkansas
- Carroll County, Arkansas
- Clay County, Arkansas
- Craighead County, Arkansas
- Franklin County, Arkansas
- Logan County, Arkansas
- Mississippi County, Arkansas
- Prairie County, Arkansas
- Sebastian County, Arkansas
- Yell County, Arkansas
- Lee County, Iowa
- Campbell County, Kentucky
- Kenton County, Kentucky
- Essex County, Massachusetts
- Middlesex County, Massachusetts
- Plymouth County, Massachusetts
- Bolivar County, Mississippi
- Carroll County, Mississippi
- Chickasaw County, Mississippi
- Harrison County, Mississippi
- Hinds County, Mississippi
- Jasper County, Mississippi
- Jones County, Mississippi
- Panola County, Mississippi
- Tallahatchie County, Mississippi
- Yalobusha County, Mississippi
- Jackson County, Missouri
- Hillsborough County, New Hampshire
- Bennington County, Vermont
 Other variations
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 (since 1960) and Rhode Island have no county level of government and thus no county seats. In Vermont, the county seats are called shire towns. County government consists only of a Superior Court and Sheriff (as an officer of the court), both located in the respective shire town. Bennington County has two shire towns (Manchester for the North Shire, Bennington for the South Shire), but both the Court and the Sheriff are in Bennington. In Massachusetts, most government functions which would otherwise be performed by county governments in other states are performed by town governments (there are no unincorporated areas in the state, that is, all land area in the state is within a town). As such, Massachusetts has dissolved many of its county governments, and the state government now operates the registries of deeds and sheriff's offices in those former counties.
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 is completely surrounded by Fairfax County, but the city is politically independent of the county.
Two counties in South Dakota (Shannon and Todd) 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.
 Lists of U.S. county seats by state
The state with the greatest number of counties is Texas, with 254, and the state with the least number of counties is Delaware, with 3.
 See also
- Administrative center
- County town, administrative centres in Ireland and the UK
- Chef-lieu, administrative centres in Algeria, Belgium, Luxembourg, France, Switzerland, and Tunisia