Yellowstone River - Montana and Wyoming Fishing
The approximately two hundred mile stretch of the Yellowstone River from the Montana state line, all the way to Billings, is full of trout. There may be a longer stretch of first class trout water in this country, but I don't know where it is.
This is not just a good trout stream, it is most certainly the best in the lower 48. No doubt about it. Foot long rainbows are just about as numerous as sunfish in the average farm pond, and twenty inch brown trout lurk in every half-way fishy pool. Most of the fishing pressure (and most of the public access) is in the section from Yellowstone National Park downstream to Livingston, but the the trout fishing is really just as good for about one hundred miles downstream from this point. Where trout numbers begin to decline outside of Billings, huge smallmouth, pike, and carp quickly take their place.
The Yellowstone's trout waters work well for wade fisherman, but those armed with a drift boat may catch a few more.