Chattanooga, Tennessee

Chattanooga is the fourth-largest city in the state of Tennessee (U.S. state) in the United States of America, with an estimated 2007 population of 168,293. The city straddles the Tennessee River in the southeast corner of the state, on the border with Georgia. It is the government seat of Hamilton County. About one half million residents live in the Chattanooga metro area.

Chattanooga is best known around the world as the subject of Glenn Miller's big band jazz standard, "Chattanooga Choo Choo." Battles in and around Chattanooga were some of the bloodiest of the American Civil War.

In 1969, the U.S. Department of Health, Education and Welfare named Chattanooga the most polluted city in the nation. The local government quickly passed legislation setting restrictions on previously unregulated emissions from industry, railroads, and coal furnaces that caused high concentrations of particulate matter. These new local standards were met in 1972, but it would take until 1989 for Chattanooga's air quality to fully comply with federal standards.