The North Fork Flathead River (Ktunaxa: kqaskanmituk ) is a 153-mile (246 km) river flowing through British Columbia, Canada, south into the U.S. state of Montana. It is one of the three primary forks of the Flathead River, a tributary of the Pend Oreille River, via Clark Fork. The river is sometimes considered the upper headwaters of the Flathead River, although the North Fork is its official name in the U.S.