This Wild and Scenic River cuts through rugged 700-foot canyon walls and offers Class IV whitewater. What’s really amazing is that no one seems to know about it. Only four outfitters are allowed three trips each per season, which lasts April through June. Go with Row Adventures (five days, $1,630). Or do it yourself: expert rafters with Class IV experience can fill out a free self-issue BLM permit at the trailhead, which is at the end of a rutted dirt track roughly 60 miles from the town of Bruneau.