Where a five-million-dollar earthen dam, the Puyallup And White River Control Project, was completed in 1948. This dam is four hundred twenty feet high—at the time the highest rock and earth-filled dam in the world. Salmon were transported over the dam by means of a special railway operated by the State department of fisheries.

The area is still open to the public for picnicking and recreation, offering awe-inspiring views of the dam. The lower part of Mud Mountain is closed off to the public, however, since it is home to the U.S. Army Corps of Engineers, Seattle District.

The dam is named after a peak on the north side of the White River at the west end of Mud Mountain Reservoir, which was named in May of 1857, by the surveyor general of Washington Territory.