Johnstown (pop. 241,247), city in southwestern Pennsylvania, in the heart of a rich coal belt on the Conemaugh River. Settled in 1770 Johnstown has long been an important iron, steel, and coal center, especially since the Civil War. In 1889, the city suffered a disastrous flood that killed more than 2,200 people when the dam at the South Fork Reservoir broke.
See also: Pennsylvania.