Question: How long is the river that contains Colter Falls?
Context: Black Eagle Dam is a hydroelectric gravity weir dam located on the Missouri River in the city of Great Falls, Montana.  The first dam on the site, built and opened in 1890, was a timber-and-rock crib dam.  This structure was the first hydroelectric dam built in Montana and the first built on the Missouri River.  The dam helped give the city of Great Falls the nickname "The Electric City."  A second dam, built of concrete in 1926 and opened in 1927, replaced the first dam, which was not removed and lies submerged in the reservoir.  Almost unchanged since 1926, the dam is 782 ft long and 34.5 ft high, and its powerhouse contains three turbines capable of generating seven megawatts (MW) of power each.  The maximum power output of the dam is 18 MW.  Montana Power Company built the second dam, PPL Corporation purchased it in 1997 and sold it to NorthWestern Corporation in 2014.  The reservoir behind the dam has no official name, but was called the Long Pool for many years.  The reservoir is about 2 mi long, and has a storage capacity of 1,710 acre.ft to 1,820 acre.ft of water. The Snoqualmie River is a 45 mi long river in King County and Snohomish County in the U.S. state of Washington.  The river's three main tributaries are the North, Middle, and South Forks, which drain the west side of the Cascade Mountains near the town of North Bend and join near the town of Snoqualmie just above the Snoqualmie Falls.  After the falls the river flows north through rich farmland and the towns of Fall City, Carnation, and Duvall before meeting the Skykomish River to form the Snohomish River near Monroe.  The Snohomish River empties into Puget Sound at Everett.  Other tributaries of the Snoqualmie River include the Taylor River and the Pratt River, both of which enter the Middle Fork, the Tolt River, which joins at Carnation, and the Raging River at Fall City. Colter Falls, also Coulter Falls, (4.3m) waterfall, nearly 0.5 mi in width, part of the Great Falls of the Missouri, on the Missouri River in north-central Montana.  Downstream of Colter Falls lies Rainbow Falls, and upstream is Black Eagle Falls.  The Lewis and Clark Expedition was known to discover Westslope cutthroat trout at the base of the falls.  The falls is now flooded in the impoundment behind Rainbow Dam.  As Rainbow Dam's reservoir is a run-of-the-river reservoir, it rarely is emptied, so the falls is rarely seen even in extreme drought.  The falls was named by Paris Gibson, founder of the city of Great Falls, Montana, while they were not named by Lewis and Clark, who measured it at "6 feet 7 inches". Rainbow Falls (originally "Handsome Falls") is a waterfall on the Missouri River in Great Falls, Montana, just upstream from Crooked Falls and downstream from Colter Falls and Rainbow Dam.  It is 47 feet (14m) high and 1,320 feet (402.3m) wide.  The waterfall is part of the five Great Falls of the Missouri.  The river spills over a sheer ledge of sandstone in the Kootenai Formation, forming the falls.  The falls used to flow with a great deal of force year-round.  In 1914 the river shortly upstream was dammed for hydroelectric power by the Rainbow Dam, which forms a run-of-the-river reservoir.  As a result, the falls can almost totally dry up in the summer with only a few narrow strips of water trickling down its face.  A railroad bridge crosses the river directly above the falls. East Falls is a neighborhood in the Northwest section of Philadelphia, Pennsylvania, United States on the east or left bank side of the now submerged Schuylkill River cataracts, the 'Falls of the Schuylkill' that became submerged as the Schuylkill Canal and Fairmount Water Works projects were completed in 1822.  The East Falls community is located adjacent to Germantown, Roxborough, Allegheny West, and Nicetown-Tioga neighborhoods.  East Falls is also adjacent to Wissahickon Valley Park.  The neighborhood runs along a stretch of Ridge Avenue that is only a few miles long, along the banks of the Schuylkill River then extends northeast to Wissahickon Avenue.  East Falls overlooks the multi-use recreational path of Fairmount Park along Kelly Drive, and is desirable for its central location, an easy commute to Center City, with easy access to several major roadways and public transportation.  East Falls continues to develop, with new housing, retail space and recreation centers in production.  It features three streets in proximity with the word "Queen" in them (Queen Lane, New Queen Street, and Indian Queen Lane), two train stations, a number of bars and restaurants, a small Korean grocer, illustrious mansions as well as some recently renovated housing that continues to increase in value. The Delaware Water Gap is recognized by the National Park Service as a National Recreation Park Area.  However it is no located in Delaware like the name suggests it is actually in New Jersey and Pennsylvania.  The map to the side will help you understand where the Delaware Water Gap is.  The reason it is called the Delaware Water Gap is because the Delaware River is the main cause of the gap and it has been working on creating the water gap for a very long.  One of the best things that the Delaware River has created in this National Park is a set of Waterfalls, Buttermilk Falls,Dingmans Falls, Silver Thread Falls , Factory Falls, Fulmer Falls, Deer Leap Falls, and Bushkill Falls The Shoshone River is a 100 mi long river in northern Wyoming in the United States.  Its headwaters are in the Absaroka Range in Shoshone National Forest.  It ends when it runs into the Big Horn River near Lovell, Wyoming.  Cities it runs near or through are Cody, Powell, Byron, and Lovell.  Near Cody, it runs through a volcanically active region of fumaroles known as Colter's Hell.  This contributed to the river being named on old maps of Wyoming as the "Stinking Water River". The Great Falls of the Catawba River mark the point at which the river encounters a series of rapids while coursing across the Piedmont Plateau on the border of Lancaster County, South Carolina, and Chester County, South Carolina, near the town of Great Falls.  Prior to the creation of the Fishing Creek Reservoir and other artificial lakes by Duke Power, the falls were a major landmark on the river.  The rapids could be heard from long distances away, while a major pre-Columbian trading path ran near the left bank.  Historically the Great Falls of the Catawba were approximately 4 miles long, with a total elevation drop of 121 feet.  (The word "falls" was an 18th-century appellation, when any river rapids and vertical waterfalls alike were both referred to as falls.)  The creation of the dams at Great Falls, South Carolina has resulted in the top 2 miles of it being completely dry (dewatered) except during times of very high flow.  The bottom portion of historical Great Falls is drowned by Cedar Creek dam, another hydroelectric project.  As of 2006, interest groups have formed in the Carolinas to restore the Great Falls by altering the dam and restoring flow to the dewatered stretch of Great Falls as part of a major restoration project of the Catawba River.  As of 2007, a new licensing arrangement has been agreed to by Duke Energy and several interested parties. The Missouri River is the longest river in North America.  Rising in the Rocky Mountains of western Montana, the Missouri flows east and south for 2341 mi before entering the Mississippi River north of St. Louis, Missouri.  The river takes drainage from a sparsely populated, semi-arid watershed of more than half a million square miles (1,300,000 km), which includes parts of ten U.S. states and two Canadian provinces.  When combined with the lower Mississippi River, it forms the world's fourth longest river system. Rainbow Dam is a hydroelectric dam on the Missouri River, 29 ft high and 1055 ft long, located six miles northeast of Great Falls in the U.S. state of Montana.  The dam is named for the downstream Rainbow Falls, a 45 ft waterfall that is the third of the five Great Falls of the Missouri.  Built in 1910, the dam furnishes water to an eight-unit hydroelectric plant with a capacity of 36 megawatts.  As the dam's power plant is located over a half-mile downstream, the flow of water over Rainbow Falls and downstream Crooked Falls is significantly reduced during the dry season.  The water from the penstocks re-enters the river a few hundred yards east of Crooked Falls.  Montana Power Company acquired the dam when it was founded in 1912, PPL Corporation purchased it in 1997 and sold it to NorthWestern Corporation in 2014.
Answer: 2341 mi