The declaration for Livingston, LaSalle, Peoria and Putnam Counties allows them to receive state recovery assistance funds. Quinn made the declaration after a tour of a central Illinois community damaged by the weekend weather.
"The state has many tools that can be mobilized quickly to help with recovery efforts, and this declaration will ensure that those assets continue to be provided for as long as they are needed," Quinn said in a statement following a tour of Dwight.
The community of about 4,300 people in Livingston County was one of the hardest hit by Saturday's storms. About 40 mobile homes and 10 other homes were destroyed or damaged by winds that were clocked at abouit 140 mph. Dozens were injured but no deaths were reported.
The National Weather Service has confirmed several tornado reports.
Residents in Kankakee, LaSalle, Peoria and Putnam counties also reported damaged homes and downed power lines.
More than 600 ComEd customers in Dwight and Streator remain without power.
Crews have restored power to about 7,700 of the approximately 8,400. Officials say the remaining customers should have power by the end of Monday.