Maximum discharge along the river is currently at the reporting a streamflow rate of cfs. This is also the highest stage along the Mazon River, with a gauge stage of ft at this location. This river is monitored from 1 different streamgauging stations along the Mazon River, the highest being situated at an altitude of ft, the .
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 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.