Spring Valley State Park, established in 1969, has a beautiful backdrop of light-gray and pink volcanic tuff and sediment around the 59-65 acre Eagle Valley Reservoir. Archaeological evidence suggests occupation dating to 5,500 B.C.E., and historic ranches were built in the late 1800s. Visitors boat, swim, fish for rainbow, tiger, and German brown trout, camp, hike, and take historic ranch tours. Waterfowl include mallards, herons, avocets, and trumpeter swans. Camping has a seven-day limit per 30-day period. Ranch Campground offers seven first-come, first-served sites, and group areas are available by reservation.