The Middle Fork Clearwater River is a short, but high volume river in northern Idaho and is the major source of the Clearwater River, a tributary of the Snake River. The Middle Fork flows west for 23 miles (37 km) from the confluence of the Selway River and Lochsa River at Lowell, to the town of Kooskia where it joins with the South Fork Clearwater River to create the Clearwater River. The Middle Fork's entire length is within Idaho County, although a small portion of its watershed extends into Clearwater County. U.S. Route 12 follows the entire length of the river.