Island Park Dam is operated by the U.S. Bureau of Reclamation in Fremont County, Idaho, United States.

The dam lies in Targhee National Forest near Island Park.

The zoned earthfill dam was built between 1937 and 1939 as part of the Minidoka Project, which provides water to irrigate farmland in Idaho's Snake River Plain.

[1] The dam provides only water storage, impounding 135,000 acre-feet (0.167 km3), which is distributed by the Cross Cut Canal to farms in Fremont and Madison counties in Idaho, and Teton County in Wyoming.

Summers feature very warm afternoons and chilly mornings, whilst winters are freezing and very snowy with an annual snowfall averaging 214 inches or 5.44 metres and reaching 375 inches or 9.53 metres between July 1974 and June 1975.