Hudson River Gorge, New York
Credit: ARO Adventures

Several hundred miles upstream of its mouth in New York City, the Hudson River cascades through a 14-mile long, whitewater-studded wilderness gorge in the Adirondack mountains. "For most of the trip, you're three miles from any road," says Adirondack River Outfitter's co-owner Ronald Smith. "Down the river is the best way to see that wilderness." April-June you'll don wetsuits for the five-hour Class IV trip, threading pounding 10-foot high waves of rapids like the Narrows and Greyhound Ledge (a wave big enough to stop a Greyhound bus.) Later in the season, the snowmelt replaced by reservoir releases, so the water is warm enough for swimsuits, and still splashy fun. As of April 1, there’s still plenty of snow in the valleys, says Smith, "which usually translates into a big-water season."