Marys River (Illinois) River basin: Marys River (Illinois) Marys River is a tributary of the Mississippi River in Illinois. It drains a small watershed between the Big Muddy River and the Kaskaskia River. It joins the Mississippi just southeast of Chester, near Kaskaskia. Because of its proximity to Kaskaskia — the capital of Illinois Territory and the first capital of the State of Illinois — Marys River was the site of early settlements leading into the interior of Illinois. Marys River is approximately in length. The following cities and towns are in the Marys River basin: Parts of the following counties are in
Illinois River (Colorado) Illinois River (Colorado) Illinois River is a tributary of the Michigan River, approximately long, in Jackson County in north central Colorado. It drains part of the North Park basin south of Walden. The Illinois River starts in the Never Summer Mountains near the continental divide, just south of Farview Mountain. It descends northward through a winding gorge, emerging into North Park at approximately above sea level. It flows northward through the valley as a winding stream, past Rand. It passes under State Highway 14 just southeast of Walden and joins the Michigan from the north just north of Walden. A