Green Valley State Park in Union County, north of Creston, centers on Green Valley Lake, an artificial lake created in 1950 as part of a postwar effort to build lakes in southwest Iowa. Its development responded in part to water shortages exposed during the 1930s, when Summit Lake in Creston dried up. Intended for both recreation and the Southwestern Federal Power Cooperative, the area was dedicated as a state park in 1953. The park preserves wetlands, woodlands, lakeshore, and prairie remnants, supports fishing, boating, trails, camping, and cabins, and later saw lake renovation, water-quality improvements, and a management plan aimed at protecting both land and water.