For more than a century, freight trains have rumbled up and over Marias Pass, skirting the south boundary of Glacier National Park, casting rolling shadows on the Middle Fork of the Flathead River below. Until recently the major threat was a grain car derailment, which on occasion left bears woozy from eating fermented grain. Today a derailment involving a 100-car train hauling highly combustible Bakken crude oil risks an environmental catastrophe unprecedented in National Park Service history.

Unexpected construction delays have led the staff at New River Gorge National River in West Virginia to push back the opening of the Meadow Creek Campground until next year.

Deep in West Virginia, the New River has cut a 1,000-foot gorge that, in places, froths with whitewater. Its V-shaped mountainsides are covered in trees. Outcrops of Nuttall sandstone packed with quartz, the gorge’s bones, show near the tops of the cliffs.

Rivers run fast and tumbling throughout the National Park System, there are streams with lazy meanders, and placid lakes perfect for dipping a paddle. This diversity poses a delightful dilemma when you have the urge to float and paddle. What follows is just a sampling of the experiences that await you, whether you have hundreds of watery miles under your paddle, or are looking for calm waters to take your youngsters.