Yellowtail Dam, Concrete arch dam in Big Horn County, Montana, United States

Yellowtail Dam is a concrete arch dam spanning the Bighorn River in Big Horn County, Montana. Its curved wall rises from the river canyon and holds back Bighorn Lake, a reservoir that reaches into the surrounding hills.

The dam was authorized in 1944 and built between 1961 and 1967 to control the Bighorn River for irrigation and power. It was first conceived as a joint project with the Crow Nation, but the land was eventually sold to the federal government.

The dam sits near the Crow Reservation, and the reservoir still touches tribal land, a reminder of the original plan for a shared project. Today, the site is a gathering spot for families who come to fish, boat, and picnic along the shore.

The dam is reached by a paved road that winds down into the canyon, with parking near the visitor center. From there, walkways and viewpoints let you see the structure up close, though some paths may be steep or uneven.

The cold, clear water released from the dam turns the lower Bighorn into a famous trout fishery. Less known is that the reservoir extends into the Crow Reservation, so parts of the lake lie on tribal land.