One of the unforeseen benefits of the North American dam-building era is all the great winter flyfishing it created in the mountain states for those of us unable or unwilling to wait until spring. These stretches of water that flow beneath dams are known as tailwaters in fishing terminology—as opposed to “freestone” which are undammed rivers.

Some of the more famous tailwaters in the country are the South Holston and Watauga Rivers in East Tennessee, the White River and Little Red in Arkansas, and the Truckee and East Walker in California and Nevada. But for winter and early spring flyfishers, nothing matches the 900-mile stretch of road between Page, Arizona, and Missoula, Montana, where dozens of legendary tailwaters run along the spine of the Rocky Mountains.

From Lee’s Ferry at the beginning of The Grand Canyon on the Colorado, to Utah’s legendary Green below Flaming Gorge Reservoir, to the unbeatable Bighorn in Montana, flyfishing in January and February can be some of the best of the year–no crowds, no mosquitoes, and plenty of hungry fish.

The majority of these waters will fish very similar to one another in the wintertime. The fish are primarily browns and rainbows, and the tactics will mostly involve nymphing with small flies like midge patterns or pheasant tails. But even the coldest day can sometimes produce hatches–midges, winter stoneflies or bluewing olives are the most common–so be sure and bring a few dries along just in case.