The average Illinois price for a gallon of regular unleaded is $2.31. This is 4 cents cheaper than last week's mean price.
The state's most expensive gas, according to AAA, can be found in the City of Chicago, at $2.68 per gallon. By contrast, Springfield has the cheapest gas, at a price of $2.07 per gallon.
Rockford's average per-gallon price is $2.21. This is three cents cheaper than last week's average.