Madison

Course

The Madison River begins in Teton County, Wyoming at the confluence of the Firehole and Gibbon rivers in Yellowstone National Park, a location known as Madison Junction. It flows west out of the park and into Montana, turning north through the Rocky Mountains of southwestern Montana to join the Jefferson and Gallatin rivers at Three Forks. The Missouri River Headwaters State Park lies at this confluence.

In its upper reaches in Gallatin County, Montana, the Hebgen Dam forms Hebgen Lake. Downstream of Hebgen Dam, the 1959 Hebgen Lake earthquake led to the formation of Quake Lake, a naturally dammed body of water that remains part of the river’s hydrology. In its middle course, the Madison Dam in Madison County, Montana creates Ennis Lake.

History

The river was named in July 1805 by Meriwether Lewis at Three Forks. The central fork of the three, it was named for U.S. Secretary of State James Madison, who later succeeded Thomas Jefferson as President in 1809. The western fork, the largest, was named for President Jefferson and the east fork for Treasury Secretary Albert Gallatin.

On August 17, 1959, a massive earthquake near Hebgen Lake triggered a landslide that blocked the Madison River, forming Quake Lake. The quake, known as the 1959 Hebgen Lake earthquake, measured 7.3 to 7.5 on the Richter scale and caused significant loss of life and property damage in the area.

Ecology

The Madison River is widely regarded as one of the finest trout fisheries in the world. It is classified as a blue ribbon fishery in Montana, where fly fisherman target brown trout, rainbow trout, cutthroat trout, and mountain whitefish.

Grizzly bears and wolves reintroduced to Yellowstone National Park roam the river valley.

According to Montana Fish, Wildlife & Parks, the Madison River supports many fish species, reflecting its varied aquatic habitats and long history of fisheries management. Both coldwater and warmwater species are present, including several native salmonids such as Arctic grayling, mountain whitefish, and westslope cutthroat trout. Introduced species like brown trout, rainbow trout, and brook trout are also well established and widely targeted by anglers.