The Henry’s Fork is one of the first rivers to swarm with salmonflies, with peak emergence on the rough-and-tumble Box Canyon stretch often coinciding with Memorial Day weekend. If you’re looking for trout measured in pounds, this is the place to be. I prefer to fish the canyon on foot, because there’s little time to thoroughly fish the pocket water from a boat. But wading here is not for the faint of heart. Unless you’re willing to chase a big trout downriver by scrambling along the boulder-choked banks, you probably won’t land him. Local Pattern: Henry’s Fork Salmonfly Contact: Henry’s Fork Anglers in Last Chance, 800-788-4479