|Origin||Greenfield Township, Grundy County, Illinois
|Mouth||Confluence with the Illinois River, Morris, Illinois
|Progression||Mazon River → Illinois → Mississippi → Gulf of Mexico|
|Length||28 mi (45 km)|
|Mouth elevation||489 ft (149 m)|
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 Illinois Department of Natural Resources (IDNR) has recently considered renaming the Mazon River. The IDNR believes that the frequent vandalism and theft of Mazon River signs is due to its current name being very similar to the well known Amazon River of South America.
The Mazon River is approximately 28 miles (45 km) in length, with the West Fork considered the main branch.
The river was named in honor of William Mason, a pioneer settler.
Cities and counties
The following cities, towns and villages are within the Mazon watershed:
The following counties are at least partly drained by the Mazon River:
- U.S. Geological Survey Geographic Names Information System: Mazon River
- U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National Map, accessed May 13, 2011
- Gannett, Henry (1905). The Origin of Certain Place Names in the United States. U.S. Government Printing Office. p. 202.