The National Weather Service told residents of Chicago to stay indoors as a ”large and extremely dangerous tornado" touched down in Woodbridge, a suburb west of the city, late on Sunday.
By 5am on Monday, officials in Naperville — a city 25 miles west of Chicago — received more than 120 incidents of damage to property, and 450 reports of power outages.
Six people were also injured in Naperville, including an individual in a critical condition. Sixteen homes were deemed uninhabitable in the aftermath.
In Woodbridge, 12 miles west of downtown Chicago, there were no initial reports of injuries on Monday but multiple reports of damage to properties, and power outages.
Matt Friedlein, a meteorologist with the National Weather Service in Romeoville, Illinois, said officials were investigating the tornado.
He indicated that it had wind speeds of 136 to 165 mph, and could have carried debris as high as 2,000 feet into the air above Chicago.
“We suspect it was one tornado. We don’t know that for certain, but based on the nature of the information and what we know about the character of this event, that’s what we’re leaning toward,” Mr Friedlein said at a briefing.
A severe threat warning was in effect until 2am.
“If there were no fatalities — and there haven’t been any reported to us — that’s great news considering the population of the area, the level of damage and the time of day, after 11pm when many people may be asleep,” Mr Friedlein added.
Pictures and video footage from the area started to appear on social media on Monday, showing houses swept away by the tornado.
Additional reporting by Associated Press