Their combined length is 535 nautical miles (991 km).
Of these waterways the Illinois is thought to be the only river large enough to support barge traffic.
In the Peoria area, there are six bridges that cross the Illinois River.
Because of the topography of the cities, alignments of the numerous state routes that cross the Illinois River can be somewhat confusing.
The Illinois River is part of a waterway system that begins in New Orleans, Louisiana and exits the Atlantic Ocean via Chicago and the Saint Lawrence Seaway.