The biggest rainbow trout I ever caught lives at the Keystone (Colorado) Village Ice Rink, a five-acre lake at 9321 feet above sea level. Here is that wonderful fish, held by Matt Campanella, a skilled fly fishing guide.
Keystone is best known for winter sports like skiing and for its eponymous conference center. The lake freezes over in winter and the ice gets a lot of skating use while trout hibernate below. These trout have no natural enemies and gorge on pellets thrown by summer tourists. That is why they are huge.
This unique fishing experience requires a reservation made directly with Keystone. Their website is keystoneresort.com/activitiesdetail/Key+-+Fly+Fishing.axd, and you can call them at (800) 328-1323. They set up a guided trip with Cutthroat Anglers, a fly-fishing shop and guide service in Silverthorne, Colorado, only a 15-minute ride from Keystone.