Hamilton County is a county located in the U.S. state of Tennessee. It is located in the southern part of East Tennessee on the border with Georgia. As of the 2020 census, the population was 366,207, making it the fourth-most populous county in Tennessee. Its county seat is Chattanooga, located along the Tennessee River. The county was named for Alexander Hamilton, the first secretary of the treasury.

Chattanooga is a city in, and the county seat of, Hamilton County, Tennessee, United States. It is located along the Tennessee River, and borders Georgia to the south. With a population of 181,099 in 2020, it is Tennessee's fourth-largest 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 Southeast Tennessee, Northwest Georgia, and Northeast Alabama.