a city and the administrative center of Kusa Raion, Cheliabinsk Oblast, RSFSR, located at the confluence of the Kusa River and the Ai (a tributary of the Ufa), 187 km west of Cheliabinsk; a railway station on the Druzhinino-Berdiaush line. Population, 22,000 (1971).

Kusa has a machinery construction plant, a cast-iron art foundry, a fine industrial stone plant, and logging and woodworking industries. The city has an evening machinery construction technicum. Kusa was founded in 1778 in connection with the construction of a foundry. It became a city in 1943. There are deposits of iron ore and marble in the area.