Big South Fork preserves 125,000 acres of the Cumberland Plateau across the Kentucky-Tennessee line, centered on the free-flowing Big South Fork of the Cumberland River and its tributaries. It is the fifth-largest National Park Service unit east of the Mississippi and is often described as the quiet alternative to Great Smoky Mountains - similar Appalachian character, a fraction of the crowds. The park was designated in 1974 to protect water quality and provide recreation opportunities for nearby populations, and it retains a distinctly rugged feel shaped as much by the area's mining and logging past as by its geology. The geology is what most visitors remember. Pennsylvanian sandstone caps softer Mississippian rock beneath, and where water has eroded the lower layers and left the hard cap intact, the plateau has produced one of the highest concentrations of natural arches in the eastern United States. Twin Arches is among the largest natural land bridges in North America. Hoodoos, rock houses, waterfalls, and 500-foot gorge walls fill out the landscape. The region averages high annual rainfall, which keeps the tributary streams cutting, and those streams feed the Big South Fork itself on its north-flowing course - one of the few rivers in the South, and one of the few undammed ones, that flows south to north. Coal and timber shaped the human landscape. The Blue Heron Mining Community in Kentucky, owned and operated by the Stearns Coal and Lumber Company until the mid-20th century, is preserved as an open-air interpretive site with ghost structures and period signage. The Big South Fork Scenic Railway runs seasonally on the old Kentucky and Tennessee line between Stearns and Barthell, another Stearns camp. The abandoned community of No Business, settled in 1796 and vacated by 1960, sits in the Tennessee backcountry. Charit Creek Lodge, a working wilderness lodge accessible only by foot, horse, or bike, operates 1.1 miles from the nearest road. Recreation is unusually diverse for a single NPS unit. More than 180 miles of horse trails support day rides and overnight pack trips, with dedicated equestrian campgrounds at Bear Creek and Station Camp. Roughly 60 miles of hiking trail range from short waterfall walks to backpacking sections of the Sheltowee Trace. Whitewater paddling, rock climbing at dozens of sandstone crags, mountain biking, hunting, and fishing round it out. Primary access is Bandy Creek (TN) and Blue Heron (KY); Oneida, Jamestown, Stearns, and Whitley City are the nearest service towns. Dark skies are exceptional, supported by adjacent state parks that hold Silver-Tier International Dark Sky status. Headquarters is in Oneida, TN.