Eagle Island State Park is a 545-acre public recreation area near Eagle, Idaho, lying between the north and south channels of the Boise River and shaped by a river landscape that gives it an island-like feel. The land entered public use in 1929 as state-owned grazing land for a penitentiary farm, then shifted to park purposes after transfers in 1977 and 1978. Formally dedicated in 1983, it developed into a year-round state park offering summer swimming, picnicking, boating, fishing, trails, and other outdoor activities, and in winter snow tubing, skiing, and snowboarding. It remains a major multiuse park in the Boise area.