The Big Hole River is a tributary of the Jefferson River, approximately 153 miles (246 km) 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.
Big Hole River near Twin Bridges, Montana
Upper Big Hole River near Jackson, Montana
The Jefferson River is a tributary of the Missouri River, approximately 83 miles (134 km) long, in the U.S. state of Montana. The Jefferson River and the Madison River form the official beginning of the Missouri at Missouri Headwaters State Park near Three Forks. It is joined 0.6 miles (1.0 km) downstream (northeast) by the Gallatin.
Confluence of Beaverhead and Big Hole Rivers forming the Jefferson near Twin Bridges, Montana
Jefferson River near Parrot Castle, October 2007
Small marine fossils can be found in the Madison Group limestone that makes up the steep, narrow section of the Jefferson River canyon.
Lewis and Clark ascended the Jefferson River in 1805 in their search for a navigable water route to the Pacific.