Big Muddy River Big Muddy River The Big Muddy River is a river in southern Illinois. It joins the Mississippi River just south of Grand Tower. The Big Muddy has been dammed near Benton, forming Rend Lake. The Big Muddy has a mud bottom for most of its length. The Big Muddy drains a watershed. In 1995, water quality was assessed as "fair" to "good". Pollution sources include agricultural practices, mining and municipalities. The watershed of the Big Muddy was covered by the Illinoian Glacier about 300,000 to 132,000 years before present. The Big Muddy basin formed after the retreat of that glacier.
Big Muddy Creek (Missouri River tributary) Fort Peck Indian Reservation. It joins the Missouri west of Culbertson. It was explored in 1805 by the Lewis and Clark Expedition, who called it Martha's River in their journals and noticed on their return voyage in 1806 that it had changed its mouth on the Missouri. Along with the Milk River and the Poplar River, it is one of three waterways in Canada that drain into the Gulf of Mexico. Big Muddy Creek has also been known as: Big Muddy River, Little Yellow River, Martha River, Martha's River, Marthas River, Marthy's River and Park River. Big Muddy Creek (Missouri