Many of the alpine lakes on the Beartooth Plateau have been stocked with trout. The hikes in are lovely, the fishing’s generally good, and Pat Marcuson details every fish-bearing Beartooth lake and stream in Fishing the Beartooths, published by Falcon Press. Remember that the road dips down into Wyoming here—buy a Wyoming fishing license in Cooke City [1] or at the Top of the World store before going after the rainbow, cutthroat, and brook trout in Beartooth Lake.
Links:
[1] http://www.moon.com/destinations/montana/the-missouri-headwaters-and-south-central-montana/absaroka-beartooth-wilderness/cooke-city-and-silver-gate