Swan Falls Dam is a concrete gravity type hydroelectric dam on the Snake River, in the U.S. state of Idaho. It is located near Murphy, Idaho.
The dam was built in 1901 to generate electricity. It is the oldest hydroelectric dam on the Snake River. In the 1990s the original power plant was replaced with a new one. The dam was built with fish passage facilities, but they proved to be very poor in performance. For this reason, among others, the C. J. Strike Dam, built upriver from Swan Falls Dam in the early 1950s, was not equipped with fish passage facilities. Thus the two dams combined to become the first artificial barrier to anadromous fish migration up the Snake River. Today Hells Canyon Dam is the first total barrier to fish migration on the Snake.
The dam and its reservoir lie within the Snake River Birds of Prey National Conservation Area. The dam and power plant were listed in the National Register of Historic Places.