Fish Lake is a reservoir located 4639ft above sea level in Jackson County, Oregon, United States. It is 35mi northeast of Medford. Originally a natural lake, it was enlarged by the 50ft tall Fish Lake Dam, which impounds the north fork of Little Butte Creek, in the Rogue River watershed.GeologyFish Lake is located between two volcanoes: Mount McLoughlin to the north and Brown Mountain to the south. Two-thousand-year-old andesite lava flows erupted from Brown Mountain surround Fish Lake's southern shore.HistoryFish Lake was originally a small natural lake. In 1898, the Fish Lake Water Company was established to help irrigate the Rogue Valley. The company proposed to enlarge Fish Lake and nearby Fourmile Lake for added water storage. The temporary Fish Lake Dam was constructed between 1902 and 1908. In 1906, Fourmile Lake Dam was constructed. The two lakes were connected in 1915 by the Cascade Canal, bringing water from Fourmile Lake in the Klamath River watershed over the Cascade Divide to Fish Lake, to supplement Little Butte Creek. The temporary dam was replaced by a permanent earthfill dam. The dam was modified again in 1922. In 1955, a new spillway was constructed. An auxiliary spillway was added in 1996. The lake is now about three times its original size.
