Copper River
also called Atna, a river of Alaska, having its source in the Copper Glacier on Mt. Wrangel and flowing in the Gulf of Alaska. The upper river flows first N. then W. through a wide plain, and the lower through defiles in the Chugach Mountains. It is about 300 miles long; its basin is about 23,000 square miles in area, and its fall is about 3,600. The name of the river was derived from the belief that it held copper in solution. It has several tributaries, the chief being the Chitna, which flows into it from the E.