- Okanogan (/ˌoʊkəˈnɒɡən/ OH-kə-NOG-ən; derived from Syilx’tsn: “rendezvous” or “meeting place”) is a city in Okanogan County, Washington, United States. The population was 2,379 at the 2020 census, down from 2,552 at the 2010 census, within the Greater Omak Area. It is the seat of Okanogan County.