Illinois River 20 miles (32 km) of its course, the Illinois is separated from the Mississippi River by only about five miles, by a peninsula of land that makes up Calhoun County. The Illinois joins the Mississippi near Grafton, approximately 25 miles (40 km) northwest of downtown St. Louis and about 20 miles upstream from the confluence of the Missouri River and the Mississippi. South of Hennepin, the Illinois River is following the ancient channel of the Mississippi River. The Illinoian Stage, about 300,000 to 132,000 years ago, blocked the Mississippi near Rock Island, diverting it into its present channel. After the
Big Annemessex River Annemessex River; the city of Crisfield rests upon its shores. Big Annemessex River The Big Annemessex River is a tributary of the Chesapeake Bay on the Delmarva Peninsula. It rises in Kingston, Somerset County, Maryland, and flows roughly southwest about in a meandering pattern, then widens into an estuary and continues about to the bay, near Janes Island State Park. Tributaries include Annemessex Creek, Holland Creek, Hall Creek, Muddy Creek, Colbourn Creek, Jones Creek and Daugherty Creek. The river is spanned once by River Road, a residential county road far from any population center. The Annemessex Creek upstream, however, is