Clark Fork River

Clark Fork Original name given by Lewis and Clark expedition: Clark's River
The Clark Fork at Missoula, Montana
Map of the Clark Fork, its main tributaries and downriver connection to the Columbia River via the Pend Oreille River.
Location
Country	United States
State	Montana, Idaho
Cities	Butte, Missoula
Physical characteristics
Source	Silver Bow Creek
• location	Butte, Silver Bow County, Montana
• coordinates	46°4′32″N 112°27′56″W / 46.07556°N 112.46556°W / 46.07556; -112.46556[1]
• elevation	6,882 ft (2,098 m)[2]
2nd source	Warm Springs Creek (Montana)
• location	Flint Creek Range, Granite County, Montana
• coordinates	46°15′39″N 113°8′12″W / 46.26083°N 113.13667°W / 46.26083; -113.13667[3]
• elevation	7,466 ft (2,276 m)[4]
Source confluence
• location	Deer Lodge County, Montana
• coordinates	46°11′12″N 112°46′18″W / 46.18667°N 112.77167°W / 46.18667; -112.77167[5]
• elevation	4,795 ft (1,462 m)[6]
Mouth	Lake Pend Oreille
• location	Bonner County, Idaho
• coordinates	48°11′0″N 116°16′9″W / 48.18333°N 116.26917°W / 48.18333; -116.26917[5]
• elevation	2,064 ft (629 m)[7]
Length	310 mi (500 km)[5]
Basin size	22,905 sq mi (59,320 km2)[8]
Discharge
• location	Whitehorse Rapids near Cabinet, ID[9]
• average	21,930 cu ft/s (621 m3/s)[10]
• minimum	762 cu ft/s (21.6 m3/s)
• maximum	195,000 cu ft/s (5,500 m3/s)
Basin features
Tributaries
• left	Bitterroot River
• right	Blackfoot River, Flathead River, Bull River

The Clark Fork, or the Clark Fork of the Columbia River, is a river in the U.S. states of Montana and Idaho, approximately 310 miles (500 km) long. It is named after William Clark of the 1806 Lewis and Clark Expedition. The largest river by volume in Montana,^[11] it drains an extensive region of the Rocky Mountains in western Montana and northern Idaho in the watershed of the Columbia River. The river flows northwest through a long valley at the base of the Cabinet Mountains and empties into Lake Pend Oreille in the Idaho Panhandle. The Pend Oreille River in Idaho, Washington, and British Columbia, Canada which drains the lake to the Columbia in Washington, is sometimes included as part of the Clark Fork, giving it a total length of 479 miles (771 km), with a drainage area of 25,820 square miles (66,900 km²). In its upper 20 miles (32 km) in Montana near Butte, it is known as Silver Bow Creek. Interstate 90 follows much of the upper course of the river from Butte to Saint Regis. The highest point within the river's watershed is Mount Evans at 10,641 feet (3,243 m) in Deer Lodge County, Montana along the Continental Divide.^[12]

The Clark Fork is a Class I river for recreational purposes in Montana from Warm Springs Creek to the Idaho border.^[13]