Hendersonville is the most populous city in Sumner County, Tennessee, on Old Hickory Lake. As of the 2020 census the city's population was 61,753. Hendersonville is the fourth-most populous city in the Nashville metropolitan area after Nashville, Murfreesboro, and Franklin and the 10th largest in Tennessee. Hendersonville is located 18 miles (29 km) northeast of downtown Nashville. The city was settled around 1784 by Daniel Smith, whose house Rock Castle, completed in 1796, is maintained as an historic site. The city is named for William Henderson, the first postmaster.