Lower Salmon Falls was a 20-foot waterfall on the Snake River in Idaho, downstream of Hagerman on the line between Twin Falls and Gooding counties. The crest was nearly a quarter mile wide, and the falls are now inundated: Lower Salmon Falls Dam was built on top of it.
The falls
The World Waterfall Database says roughly half of the old falls now lies under the reservoir, and the rest of the ledge stays dry except when the dam spills at high water. The dam is 38 feet high and 983 feet long, including a 180-foot overflow section, and backs up a reservoir of 750 acres that runs 6.6 miles upstream. A 510-foot fish ladder runs alongside.
Getting there
Idaho Power runs Lower Salmon Falls Park, a 4-acre day-use area on Justice Grade Road off Idaho Highway 30 in the Hagerman Valley. Day use is free. The park has large parking for cars and boat trailers, a boat ramp and docks, fishing access, interpretive signs, accessible restrooms and a picnic shelter that rents for $75 a day in summer, including a $25 non-refundable reservation fee, plus tax.
When to go
Water crosses the exposed part of the old ledge only when the spillway is in use at high water.
On site
Twin Falls County prohibits entry below the high-water mark between the downstream side of the dam, spillway and powerhouse and the buoy line upstream. Stay out of that zone.
History and name
The Greater Shoshone and Twin Falls Water Power Company built the power plant in 1910. Idaho Power bought it in 1916 and rebuilt it in 1949; with four generators it produces 60 megawatts and forms part of the company's Mid-Snake Projects with the Upper Salmon Falls and Bliss dams.
Nearby
West Canal Falls is about 2.5 miles away, Malad Falls on the Malad River about 3.1 miles, and Upper Salmon Falls, the next dam up the Snake, about 5.2 miles. The town of Wendell is about 11.2 miles away.
Distances are straight-line.
![[IDAHO-B-0070] Snake River - Lower Salmon Falls [IDAHO-B-0070] Snake River - Lower Salmon Falls](https://fallsdiscovery.com/wp-content/uploads/2026/09/5569429109_8b880ebddb_b-768x482.jpg)