The Gallatin River is about twelve miles long from its origin at the confluence of the West and East Gallatin rivers to Three Forks, Montana, where it joins the Jefferson and Madison rivers to form the Missouri River. The river flows through a narrow valley consisting of agricultural and grazing lands at elevations less than 5,000 feet. The banks are primarily undercuts, and long, deep pools provide much of the fish cover. Except for the East and West Gallatin rivers, tributaries to the Gallatin River are limited to a few spring creeks.
The Yellowstone River originates in Wyoming and flows through Yellowstone National Park before entering Montana at Gardiner. From the park boundary to Livingston, the river flows north through Paradise Valley, flanked by the Absarokee Mountains on the east and the Gallatin Range on the west. It continues in a northeasterly direction from Livingston and meets up with the Missouri River just across the North Dakota border. The Yellowstone has survived as one of the last, large, free flowing rivers in the continental United States. Lack of mainstem impoundments allows spring peak flows and fall and winter low flows to influence a unique ecosystem and aesthetic resource. From the clear, coldwater cutthroat trout fishery in Yellowstone National Park to the warmer water habitat at its mouth, the river supports a variety of aquatic environments that remain relatively undisturbed. The adjacent terrestrial environment, through most of the 550 Montana miles of river, is an impressive cottonwood-willow bottomland. The river has also been a major factor in the settlement of southeastern Montana, and retains much cultural and historical significance.
The Madison River originates in Yellowstone National Park at the junction of the Firehole and Gibbon rivers and flows in a northerly direction for 140 miles to Three Forks, Montana, where it joins the Jefferson and Gallatin rivers to form the Missouri River. From its source in the park, the Madison flows across a high conifer-forested plateau, its journey interrupted by two man-made impoundments: Hebgen Reservoir, located one and one-half miles below the park boundary, and Ennis Reservoir, 58 miles downstream from Hebgen. Just below Hebgen, the Madison feeds Quake Lake, a natural lake formed by an earth slide during a major earthquake in 1959. From Ennis Reservoir the Madison flows through Bear Trap Canyon before entering the lower Madison River valley for its final 18 miles. The Madison is one of Montanas premier wild trout rivers. Due to its national reputation, heavy fishing pressure, good access, high scenic value, and excellent wild trout populations, it has been classified as a Blue Ribbon trout stream. The Madison is also the home of wild trout management, where the results of a controversial study in the early 1970s introduced a shift in management emphasis nationwide, from stocking trout to population monitoring, harvest regulation, and habitat protection. A number of challenges exist to wild trout fisheries in the Madison River, such as whirling disease, increased angling pressure, and drought.
The Bighorn River is rated one of the worlds finest trout streams because of its abundant trout, dense insect hatches, and easy accessibility. Prior to 1965, the Bighorn was a warm, silty stream that flowed out of the spectacular Bighorn Canyon northward into the eastern Montana prairie. With the completion of Yellowtail Dam at Fort Smith, Montana, most of the rivers silt load was trapped behind the dam. The river below was transformed into a cold, clear tailwater, much like a giant spring creek - an ideal habitat for trout. The Bighorn Rivers headwaters lie in the Absaroka, Bighorn, and Wind River mountain ranges of northwest and north central Wyoming. From below the Montana-Wyoming state line, the mainstem flows through Bighorn Canyon to Yellowtail Dam, a 47-mile-long passage between the northern end of the Bighorn Mountains and the southeast margin of the Pryor Mountains. The canyon, its sandstone and limestone cliffs rising steeply hundreds of feet, holds the waters of Bighorn Lake. From the Afterbay Dam, a reregulating facility 2 miles downstream, the Bighorn River journeys 84 miles - through the Crow Indian Reservation, past massive tree-dotted ramparts and rock outcroppings, beside rolling hills, grasslands, and pine-covered ridges - and joins the Yellowstone River near the old settlement of Bighorn, just east of Custer, Montana.