Even if the notion of the Missouri headwaters doesn’t automatically stir your blood, a visit there probably will. There’s something big about the place where three lively trout streams join up to make their way across the plains that gives the spirit an almost geological uplift.
All three of the Missouri’s forks come straight from the mountains. The Madison Range flanks the Madison Valley to the east; to the west are the northerly glacier-cut Tobacco Root Mountains and the southerly low Gravelly Range.
The Madison River , which forms the middle fork of the Missouri, starts in Yellowstone National Park and joins with the Jefferson and the Gallatin  at Three Forks. Mention of the Madison quickens the pulse of anglers across the United States; people come from all over to fish here, and the valley sports several guest ranches to accommodate them.
The Madison Range has obvious current geologic activity. The eastern front is moving along a fault. A lurching move in August 1959 jacked the mountains up and dropped the valley floor. The southern end of Hebgen Lake  (just west of Yellowstone National Park) rose, the northern end dropped, and a rock slide buried campers and blocked the Madison River, forming Quake Lake .