Randall Creek Recreation Area lies just downriver from Fort Randall Dam, the first dam in South Dakota completed under the Pick-Sloan Plan by the U.S. Army Corps of Engineers in 1956. From there, the Missouri River remains free-flowing for the next 39 miles to just above Lewis and Clark Lake, with conditions similar to those experienced by the Lewis and Clark Expedition more than two hundred years ago, and beyond Gavins Point Dam another 59 miles of free-flowing river are also part of this Water Trail and the Missouri National Recreational River. Built in 1856, Fort Randall Military Post played a strategic role in many events on the northern plains from the frontier and treaty periods through the settlement era; its cemetery holds settlers, Indian interpreters, and military personnel, and although the fort was abandoned in 1892, ruins including a chalkstone chapel remain below the present dam. One of six major Missouri River dams, Fort Randall Dam was completed in 1956, named for Fort Randall Military Post and Colonel Daniel W. Randall, and the reservoir behind it, Lake Francis Case, was named for South Dakota U.S. Senator Francis H. Case. Old Baldy, first encountered by Lewis and Clark on September 7th, 1804, rises 70 feet above the surrounding bluffs, and nearby they found prairie dogs previously unknown to scientists. The river bluffs expose the Niobrara Formation, created about 85 million years ago during the Cretaceous Period and rich in fossils including coccoliths, foraminifera shells, fishes, marine and flying reptiles, and toothed birds. This reach also supports bald eagles in mature cottonwood habitat, including Eagle Roost Area, a National Natural Landmark, and a segment of the Karl E. Mundt National Wildlife Refuge, where more than 1,000 acres provide habitat for 100 to 300 bald eagles and more than 200 other bird species. The 39-Mile and 59-Mile Districts of the Missouri National Recreational River are among the last relatively natural stretches of the Missouri, protected under the Wild and Scenic Rivers Act for their natural, cultural, historic, scenic, and recreational values and as part of the Lewis and Clark National Historic Trail.