The Lower Saint Croix protects 52 miles of the St. Croix River from the Taylors Falls Dam downstream to the river's confluence with the Mississippi at Prescott, WI. Added to the National Wild and Scenic Rivers System in 1972, it was the first riverway segment Congress added to the system after the 1968 act's passage. The Lower Saint Croix is administratively distinct from the broader Saint Croix National Scenic Riverway upstream but is managed as part of the same unit. The arrangement is split: the upper 27 miles, from Taylors Falls down to the Boomsite near Stillwater, are administered federally by the National Park Service, while the lower 25 miles down to the Mississippi are state-administered jointly by Minnesota and Wisconsin under a Secretarial designation granted in 1976. The geology immediately below the Taylors Falls Dam is as dramatic as anywhere on the river. The Dalles of the St. Croix expose billion-year-old basalt cliffs of the failed Midcontinent Rift, carved by glacial meltwater into deep potholes, sheer walls, and narrow channels now preserved within Minnesota's and Wisconsin's adjoining Interstate State Parks. Below the Dalles the river broadens, passes a working landscape of bluffs and floodplain forest, and is joined by the Apple River. At Stillwater the channel widens dramatically into Lake St. Croix - a 23-mile natural riverine lake not formed by a dam but by sedimentation at the Mississippi confluence. The lake averages a mile or more in width and is deep enough to support sailing and keelboat traffic. The Lower Saint Croix is heavily used, in part because it threads the edge of the Minneapolis-Saint Paul metro. The character shifts steadily downstream from wild upper water to active river towns. Stillwater, MN - often cited as one of the prettiest small river cities in the upper Midwest - sits at the head of Lake St. Croix. Hudson, WI, Afton, MN, and Prescott, WI follow along the lake. The river supports power boating, sailing, paddling, rock climbing on the basalt walls, fishing, and hiking, with a seasonal mix of waterfront restaurants, marinas, and historic town architecture contributing to the visitor draw. Primary paddle access on the NPS-managed segment includes Taylors Falls, Osceola Landing, William O'Brien State Park, and the Boomsite. On the state-administered segment, public launches appear at Stillwater, Afton, Hudson, and Prescott. The Lower Saint Croix shares visitor contact and administration with the upstream unit at St. Croix Falls, WI.