There are 115 earthquake incidents in Illinois on record since 1931. The state averages 1 earthquakes per year. The largest earthquake on record for Illinois occurred on 03/27/1974, with a depth of 10.0 miles and a magnitude of 5.6 on the Richter scale in St. Clair County, IL.
Yearly Average Number of Earthquakes in Illinois
Total Number of Earthquakes in Illinois since 1931