Smith County is a county in the U.S. state of Tennessee. As of the 2020 census, the population was 19,904. Smith County is located in the region of the state known as Middle Tennessee. Its county seat is Carthage. The county was organized in 1799 and is named for Daniel Smith, a Revolutionary War veteran who made the first map of Tennessee and served as a United States senator.

Carthage is a town in and the county seat of Smith County, Tennessee, United States; it is part of the Nashville Metropolitan Statistical Area. The population was 2,306 at the 2010 census. It is located on the Cumberland River, which was important to its early development. It is likely best known as the hometown of former Vice President and Senator Al Gore of the Democratic Party and his father, Senator Albert Gore, Sr. The younger Gore announced his 1988 and 2000 presidential bids, as well as his 1992 vice-presidential bid, from the steps of the Smith County Courthouse.