The Raker Act was an act of the United States Congress that permitted building of the O'Shaughnessy Dam and flooding of Hetch Hetchy Valley in Yosemite National Park, California. It is named for John E. Raker, its chief sponsor. The Act, passed by Congress in 1913 during the Wilson administration, specified that because the source of the water and power was on public land, no private profit could be derived from the development. The plan for damming the valley was fought for years by John Muir. Construction of the dam was finished in 1923.
There have been ongoing allegations that the Act is being breached by private profits being made; and there have also been several campaigns aimed at removing the dam and restoring the valley.