The main stem of the Whitewater River is formed by the confluence of the North Fork Whitewater River and Middle Fork Whitewater River at Elba, and is joined by the South Fork Whitewater River, just downstream. The North Fork flows through Wabasha, Olmsted, and Winona counties, with a "channel length of 47 km" (c. 30 miles). The upper branches of the Whitewater River system including the portion that flows through Whitewater State Park are designated trout streams. Native brook, wild brown and occasionally stocked rainbow trout populate the streams.