County seat
A county seat is an administrative center, or seat of government, for a county or civil parish. The term is used in the United States, Canada, Taiwan and Romania. In the United Kingdom and Ireland, county towns have a similar function.
Function
In the United States, counties are the administrative subdivisions of a state. Counties administer state law at the local level as part of the decentralization of state authority. In many states, state government is further decentralized below the county level by dividing counties into incorporated cities and towns and/or unincorporated civil townships, in order to provide local government services. 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, and hall of records, are located in the county seat, though some functions may also be conducted in other parts of the county, especially if it is geographically large.