Okanogan County covers 5,281 square miles, making it the third largest county in the continental United States. Only 30% of the land within the county is in private ownership due to the amount of state and federal land. The Colville Indian Reservation, located in the southeast corner of the county, occupies approximately 700,000 acres of Okanogan County and is an integral part of the heritage of the county.

Several major rivers flow in Okanogan County including the Columbia River, the Methow River, the Chewuch River, the Twisp River, the Similkameen,  and the Okanogan River.  Some of these rivers originate in the mountains of British Columbia and flow south across the border into the United States.  Okanogan County overlaps with 4 watersheds, the Kettle, Methow, Foster Creek and Okanogan.

A watershed is a geographic area of land bounded by topographic features and height of land that drains waters to a shared destination. Watersheds come in all shapes and sizes. No matter where you are, you're in a watershed! Okanogan county encompasses or crosses into 4 watersheds or Water Resource Inventory Areas (WRIA).

∂ Foster Creek (WRIA 50),

∂ Kettle (WRIA 60),

∂ Methow (WRIA 48), and

∂ Okanogan (WRIA 49)

In each of these watersheds water resources planning and management is occurring in one form or another - and Okanogan County is involved.