Beaverhead River

The Beaverhead River flows north from Clark Canyon Reservoir through the ranchlands of southwest Montana to its confluence with the Big Hole River near Twin Bridges, where together they form the Jefferson — one of the three forks of the Missouri that Lewis and Clark named in 1805. The Beaverhead is a tailwater fishery of national caliber: cold, clear releases from Clark Canyon Dam sustain dense populations of brown and rainbow trout in a narrow, willow-lined channel that winds through hay meadows and cottonwood bottoms. The river is small — rarely more than 60 feet wide — and the fishing is technical. Long leaders, small flies, and precise presentations define the Beaverhead style. The canyon section below the dam, where the river cuts through eroded bluffs and basalt formations, is the most scenic stretch. This is not a whitewater river. It is a float-fishing river, one of the best in Montana, in a valley that Sacagawea recognized as her homeland when she returned with the Corps of Discovery.

The Beaverhead Valley occupies a structural basin within the Northern Rockies. The canyon section below Clark Canyon Dam cuts through Tertiary volcanic and sedimentary formations, exposing eroded bluffs and occasional basalt columns. The valley floor is deep alluvium deposited by Pleistocene glacial outwash.

The Beaverhead supports one of the highest densities of brown trout per mile in Montana. Tailwater conditions from Clark Canyon Dam create a cold, stable environment that sustains year-round insect hatches and consistent trout growth rates.