Missouri National Recreational River protects the last substantial reaches of the Missouri River that still look and behave the way Lewis and Clark described. Roughly 100 river miles are preserved along the Nebraska-South Dakota border in two separate districts, with Lewis and Clark Lake - the impoundment behind Gavins Point Dam - separating them. The 59-Mile District runs from Gavins Point downstream to Ponca State Park. The 39-Mile District extends from Fort Randall Dam downstream to Running Water, South Dakota, and also encompasses the lower 20 miles of the Niobrara River and the lower 8 miles of Verdigre Creek at their confluences with the Missouri. The reason the unit exists is almost entirely negative - these two reaches escaped the dam-and-channelize treatment that transformed the rest of the Missouri. Downstream from Sioux City the river is a navigation channel, stabilized and confined; upstream it is a chain of reservoirs. In between, the water here still meanders. It moves sandbars, cuts chutes, piles up snags, strands islands, and works its floodplain the way a Great Plains river is supposed to. That behavior supports federally listed species that depend on open sandbars and shallow backwaters - interior least tern, piping plover, pallid sturgeon - and maintains cottonwood and willow floodplain forest that continues to regenerate on fresh sediment. The 39-Mile District runs between steep, dissected chalkstone bluffs of Niobrara Formation and Pierre Shale; the 59-Mile District opens into a wider, more braided valley. The river carries unusually deep cultural weight. It was the principal corridor for Paleo-Indian and later Mandan, Omaha, Ponca, Sioux, and Arikara peoples, and it remained the primary highway of westward American expansion. The Lewis and Clark expedition spent significant time along this exact reach in 1804 and on the return in 1806. Four sites within the unit sit on the National Register of Historic Places: Spirit Mound, the hill Lewis and Clark climbed on August 25, 1804; Old Baldy; Fort Randall, one of the earliest permanent military posts on the upper Missouri; and the Ponca Agency, associated with Standing Bear and the 1879 case that affirmed Native Americans as persons under US law. Recreation ranges from motorized boating, canoeing, and kayaking to birding, hunting, and fishing for walleye, paddlefish, sauger, smallmouth bass, and channel catfish. Water levels swing with dam releases - anything from a few inches to more than ten feet - so paddlers need to pay attention to gauge conditions. The unit is administered jointly with Niobrara National Scenic River. Primary visitor contact is at the Lewis and Clark Visitor Center near Yankton, SD.