Kosan is a kun, or county, in Kangwà Ân province, North Korea.
The county is predominantly mountainous, with a central basin. Its highest point is Chuaesan. Major streams include the Namdaech'à Ân, Ryongjiwà Ânch'à Ân, and Namsanch'à Ân. The county contains 13 reservoirs, and Forestland covers approximately 63.8% of its area.
Kosan county is divided into 1 Ã Âp (town) and 24 ri (villages):
Agriculture dominates local industry in Kosan, with crops including rice, maize, millet, wheat, barley, soybeans, and red beans. The region is particularly noted for its abundant production of fruit.
Mining is widely developed, exploiting the local deposits of gold, silver, copper, iron, limestone, lead, zinc, gypsum, and other minerals.
Kosan county is served by the Kangwà Ân Line of the Korean State Railway.