Big Muddy Creek (Missouri River tributary) Big Muddy Creek (Missouri River tributary) Big Muddy Creek is a tributary of the Missouri River, approximately 191 mi (307 km) long, in the Canadian province of Saskatchewan and the U.S. state of Montana. It flows through the Big Muddy Badlands. It rises in southern Saskatchewan at Willow Bunch Lake, on the plains north of the international border and approximately 20 mi (32 km) northwest of Big Beaver. It flows southeast through the Big Muddy Badlands and through Big Muddy Lake, then south into Sheridan County, Montana, past Redstone, then east, past Plentywood, then south, forming the eastern border of
Big Thompson River tributary flows east, through the town of Glen Haven, where it merges with the Big Thompson River in the town of Drake, in the Big Thompson Canyon. From Lake Estes, the river descends 1/2 mile (800 m) in elevation through the mountains in the spectacular 25 mi (40 km) Big Thompson Canyon, emerging from the foothills west of Loveland. It flows eastward, south of Loveland across the plains into Weld County and joins the South Platte approximately 5 mi (8 km) south of Greeley. It receives the Little Thompson River approximately four mi (6 km) upstream from its mouth. Water