Chattanooga is the fourth-largest city in the U.S. state of Tennessee, with a population of 167,674 as of the 2010 census and 171,279 as of May 2013. It is the seat of Hamilton County. Located in southeastern Tennessee on Chickamauga Lake and Nickajack Lake, which are both part of the Tennessee River, Chattanooga lies approximately 120 miles (190 km) to the northwest of Atlanta, Georgia, 120 miles (190 km) to the southwest of Knoxville, Tennessee, about 135 miles (217 km) to the southeast of Nashville, Tennessee, about 120 miles (190 km) to the northeast of Huntsville, Alabama, and about 148 miles (238 km) to the northeast of Birmingham, Alabama. Chattanooga abuts the Georgia border and is where three major interstate highways meet: I-24, I-75, and I-59.
The city, which has a downtown elevation of approximately 680 feet (210 m), lies at the transition between the ridge-and-valley portion of the Appalachian Mountains and the Cumberland Plateau. The city is therefore surrounded by various mountains and ridges. The official nickname for Chattanooga is the Scenic City, being reinforced by the city's growing national reputation as a haven for numerous outdoor activities. Several unofficial nicknames include River City, Nooga, Chattown, and Gig City, demonstrating Chattanooga's claims that it has the fastest internet service in the Western Hemisphere.
Chattanooga is internationally known for the 1941 gold record song "Chattanooga Choo Choo", which was popularized by Glenn Miller and his orchestra.
Chattanooga is home to the University of Tennessee at Chattanooga (UTC) and Chattanooga State Community College.
A unique distinction for Chattanooga is the fact that the city has its own typeface, Chatype, which was launched in August 2012. This marks the first time that an American city has its own typeface and also the first time a crowd-funded custom-made typeface has been used for any municipality in the world.
Since 1990, Chattanooga has been recognized as a Tree City USA community.