Mazon River

The Mazon River or Mazon Creek (), is a tributary of the Illinois River in the United States. The confluence is near Morris, Illinois. The Mazon River is associated with the Mazon Creek fossils of the Francis Creek Shale, which are also exposed in strip mines and quarries near the River. This fossil bed includes well-preserved fossils from the Pennsylvanian period of the Paleozoic era and is a world-famous Lagerstätten site. The Mazon River is approximately in length, with the West Fork considered the main branch. The river was named in honor of William Mason, a pioneer settler.