The Shields is a small, overlooked Yellowstone tributary running down its own quiet valley north of Livingston. It's mostly private water, so access is the puzzle here, but where you can get on it there are browns and rainbows in the willowy bends that see hardly any pressure. It draws down and warms in high summer, so it's a spring and early-summer river, and an autumn one. The kind of little river that doesn't make any lists and rewards the angler willing to knock on a door and ask.

• Mixed

• Aquatic life: Impaired