The Simpson runs almost through the middle of Coyhaique, which makes it the most convenient serious trout water in Aysén — you can be casting inside the hour after landing. It flows through its own national reserve in a steep, forested valley, glacial-volcanic in origin, with braided runs and pocket water that suit both nymph and streamer work. What makes the Simpson's reputation, though, is the terrestrial fishing: foam hoppers, Chernobyl Ants and Fat Alberts thumped against the bank through the warmer months bring browns and rainbows up from cover in a way that few rivers manage so reliably. It's forgiving water for a first Patagonian river, and good enough that plenty of visiting anglers never feel the need to go further.

• Volcanic glacial