Ducktown, city (1990 pop. 421), Polk co., SE Tenn., near Ga.-N.C.-Tenn. border, 50 mi/80 km E of Chattanooga; 35°02'N 84°23'W. Smelting center in copper-mining region; large sulphuric acid plant. Smelter fumes, by destroying plant growth, have caused deep erosion of region.