At least two people are dead and several others are injured, according to Illinois State Police and the LaSalle County Coroner.
Multiple vehicles were involved in the crash, with some fire involved, ISP said.
The crash happened about four miles west of Ottawa.
Chopper 7 HD over fiery I-80 crash near Ottawa
Officials have not released information about how many people may be injured or their condition.
Both westbound lanes on I-80 near mile marker 85 were closed for several hours. As of 2:37 p.m., all lanes have been reopened according to an ISP tweet.
This is a developing story. We will update with more information when it becomes available.