Johnson's Shut-Ins State Park

A shut-in is a stretch where a river is confined to a narrow channel in hard rock. Here the East Fork of the Black River follows fractures and joints in erosion-resistant rhyolite porphyry and dark diabase dikes, and the sand and gravel it carries have cut potholes, chutes and small gorges. It is one of Missouri's best examples, the center of a 180-acre natural area, and a walkway leads to an overlook above the pothole chutes. The park holds 17 natural communities and more than 850 plant species, about 40 percent of the state's.

Osage hunters came into these mountains, but most settlers preferred the river valleys. The Johnston family, Scots-Irish from Appalachia, had a farm here by 1829, and three generations worked it. Joseph Desloge of St. Louis assembled most of the park over 17 years and gave it to the state in 1955.

At 5:12 a.m. on December 14, 2005, the Taum Sauk upper reservoir on Proffit Mountain, kept full by pumping, was overtopped and gave way. The park puts the release at 1.3 billion gallons. It came down the mountainside carrying trees and boulders, scoured the valley and wrecked the campground and day-use area. Missouri's Public Service Commission later called the utility's decision to keep operating with faulty gauges reckless. Swimming in the shut-ins resumed in 2009 in a rebuilt park. Food, drinks in disposable containers, coolers and alcohol are not allowed past the Shut-Ins Trail trailhead.