The Big Hole River is a tributary of the Jefferson River, approximately 153 miles long, in Beaverhead County, in southwestern Montana, United States. It is the last habitat in the contiguous United States for native fluvial Arctic grayling and is a historically popular destination for fly fishing, especially for trout.HistoryAt the time Lewis & Clark "discovered" the Big Hole River watershed, it was a buffer zone between several rival Native American tribes including the Nez Percé, Shoshone, Coast Salish, and Blackfeet. Lewis & Clark considered navigating up the Big Hole River, but chose the slower-flowing Beaverhead River instead. Trappers from both the Hudson's Bay Company, the North West Company and the American Fur Company exploited the region from about 1810 to the 1840s. Miners and homesteaders settled the area between 1864 and the early 1900s.In 1877 the U.S. troops under John Gibbon fought the Nez Percé Indians along the Big Hole River, during the Nez Perce War in the Battle of the Big Hole. The site of the battle along the North fork of the Big Hole is preserved as the Big Hole National Battlefield.