Illinois City (ZIP code 61259) is an unincorporated community in the U.S. state of Illinois, across the Mississippi River from Muscatine, Iowa. It has a population of 125 people.
It is in lower Rock Island County, on Illinois Route 92.
Coordinates: 41°23′51″N 90°53′59″W / 41.3975305°N 90.8995898°W / 41.3975305; -90.8995898
‡This populated place also has portions in an adjacent county or counties