Illinois gas prices are up by more than $1 per gallon. How high could they get?
The average gas price in Illinois has risen by nearly $1.20 per gallon in the past month, and motorists may not see relief soon.
The steep increase is primarily due to the United States’ war with Iran, which has led to an Iranian blockade of the Strait of Hormuz, a critical shipping route for the world’s oil. The average price of regular unleaded gas in Illinois has reached $4.228 as of Wednesday, while the national average is $3.983.
When the Strait of Hormuz is closed, research shows oil prices will typically spike to about $100 per barrel, Frank Manzo IV, an economist with the Illinois Economic Policy Institute, said in a March 20 interview with the News-Democrat.
“That’s basically where we’re at already,” Manzo said.
If the waterway remains closed for three months, oil is likely to see another $60 per barrel increase, he continued.
Generally, every $10 increase in the price of a barrel is linked to a 25-cent-per-gallon increase in the price of unleaded gasoline, Manzo said. So, if the route remains closed, the average price of unleaded gasoline could potentially surpass $5.72 per gallon in Illinois by the end of May.
Even if the strait does open up soon, gas prices won’t immediately fall, Manzo said, because oil production in the Middle East has largely stopped due to a lack of storage space for the oil while it can’t be transported. It could take anywhere from days to weeks for producers to catch up after the strait reopens.
“That’s why my expectation is that gas prices remain high and potentially continue to climb,” Manzo said.
Another important factor in Illinois’ gas prices is the state’s gas tax, which is higher than most states’. Through June 30, the Illinois Motor Fuel Tax rate is set at 48.3 cents per gallon of gasoline and 55.8 cents per gallon of diesel, though the rates are tied to inflation and are likely to increase July 1.
From 2018 to 2019, the Illinois gas tax saw a steep increase from 19 to 39 cents under the Rebuild Illinois Capital Program, a $25 billion-plus infrastructure investment plan.
How can you save at the pump?
Auto club AAA offers an online tool where you can search for gas stations along your route, including pricing. GasBuddy is another option, offering an app to search for cheaper gas and a U.S. gas price map. As of March 25, GasBuddy shows crowdsourced prices of $3.96 at a Conoco in Belleville, $3.97 at a Caseyville Circle K and $3.99 at a Lebanon BP.
Upside offers cash back on gas purchases, as well as a map to locate the most affordable locations near you.
More money-saving tips to consider include using any cash-back offers your credit card company may have, checking if your company reimburses you for work trips, downloading gas station apps for offers and buying your gas with cash.
Additionally, if you happen to live near a Metro station, public transportation can be a more affordable alternative to driving.
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This story was originally published March 25, 2026 at 11:12 AM.
