Guernsey State Park in Wyoming centers on Guernsey Reservoir on the North Platte River and is known both for recreation and for its unusually well-preserved Civilian Conservation Corps landscape. Its modern development followed construction of Guernsey Dam in 1925–1927, and from 1934 to 1939 CCC crews built the park’s recreational facilities in the first collaboration between the National Park Service and the Bureau of Reclamation. Wyoming assumed management in 1957. In 1997 the park’s CCC-era district became a National Historic Landmark District with 60 contributing resources. The park also connects to western migration through the Oregon Trail Ruts and nearby Register Cliff.