Omak Lake is a saline endorheic lake in the U.S. state of Washington, within the Greater Omak Area. The lake covers 3244 acre at an elevation of 950 ft and is fed by three small creeks. With a volume of 705,000 acre.ft and depth of 325 ft, Omak is the largest saline lake in Washington. The name Omak comes from the Okanogan placename [umák]. Omak Lake occupies a former channel of the Columbia River. The Okanagan people once believed that Omak Lake was inhabited by spirits, and avoided the area.