Chattanooga is a city in Hamilton County, Tennessee, United States, and its county seat. It is located along the Tennessee River and borders Georgia to the south. The population was 181,099 at the 2020 census, and was estimated at 191,496 in 2024. It is Tennessee's fourth-most populous city and one of the two principal cities of East Tennessee, along with Knoxville. It anchors the Chattanooga metropolitan area, Tennessee's fourth-largest metropolitan statistical area, as well as a larger three-state area that includes southeastern Tennessee, northwestern Georgia, and northeastern Alabama.