Bitterroot River, c.97 mi/156 km long, SW Mont.; rises in S Ravalli co.; flows N past Hamilton to join the Clark Fork R. 5 mi/8 km W of Missoula. A R.C. mission was built in the river valley in 1841, and the missionaries are credited with establishing farming in the area. The Bitter Root project irrigates c.27 sq mi/70 sq km. The W fork of the Bitterroot R, rises in far S Ravalli co., surrounded on 3 sides by Idaho state line and crest of Bitterroot Range, flows N through Painted Rocks L. The E fork of the Bitterroot R. rises at Continental Divide, SE Ravalli co., and flows W, both forks c.40 mi/64 km long.
