Madison River Drainage Professional Review and Guide
"Madison Junction to Hebgen Dam The Madison is the middle of three rivers (along with the Gallatin and the Jefferson) that join to form the Missouri River. Lewis and Clark named the river after James Madison, President Thomas Jefferson’s Secretary of State who later became the fourth president of the United States. Madison Junction, where the river is formed by the confluence of the Gibbon and the Firehole, is also the purported birthplace of the national park concept. Yellowstone National Park was said to have been hatched as a consequence of campfire discussions of the Washburn party in 1870, as they completed the first serious exploration of the area since the heyday of the mountain-men fur trappers of the 1820s and 1830s.
From its source, the river flows west into Montana and the lake impounded by Hebgen Dam. In addition to the Firehole and Gibbon Rivers, the Madison drainage picks up several other tributaries in this section. This eTrail contains information on the Madison River (Madison Junction to Madison River Bridge), Hebgen Lake, South Fork of the Madison, Duck Creek, Grayling Creek, and Tepee Creek."