Under the Tennessee Constitution, counties are an extension of the state and are deemed political subdivisions of the state created in the exercise of its sovereign power to carry out the policy of the state. Counties, as the creation of the state, are subject to control by Tennessee's legislature, known as the General Assembly. Although the General Assembly has very broad powers to deal with county government, the state's constitution places some limitation on its discretion regarding counties.

A long line of Tennessee Supreme Court case law has held that counties have no authority except that expressly given them by statute or necessarily implied from it. Bayless v. Knox County, 286 S.W.2d 579 (Tenn. 1955). Although statutes are the primary source of county authority, the Tennessee Constitution does contain a few provisions specifically addressed to county government. Counties have only the implied power to do acts necessary to enable them to exercise their expressed powers or to accomplish the objectives for which they were created.