Illinois Gas Prices This Week

In the EIA’s July 2026 (revised August 2026) table of motor fuel taxes, Illinois’s state taxes and fees on gasoline total 71.7¢ a gallon, the 2nd-highest of the 50 states and D.C. The 51-jurisdiction average is 33.8¢, and the federal tax adds 18.4¢ everywhere. Illinois doubled its excise tax from 19¢ to 38¢ on July 1, 2019, the first increase since 1990, and has adjusted it every July 1 since for inflation. A law signed in June 2026 suspended that year’s inflation increase for six months, through December 31, 2026. The state also collects sales tax on gasoline, which the EIA counts in its figure, and some counties and cities, including Chicago, add their own per-gallon taxes, which it does not.

Illinois has four refineries with a combined capacity of about 1.05 million barrels a day, according to the EIA: WRB Refining at Wood River, across the Mississippi from St. Louis (345,000 barrels a day), ExxonMobil at Joliet (267,000), Marathon at Robinson (253,000), and Citgo’s plant at Lemont (about 188,000). Joliet and Lemont are in the Chicago area.

The Chicago area (Cook, DuPage, Kane, Lake, McHenry, and Will counties and parts of Grundy and Kendall) requires federal reformulated gasoline; the rest of the state sells conventional gasoline. A stricter summer volatility limit for the Illinois side of the St. Louis area ended in 2014. Illinois has no weekly EIA price series; across the Midwest region, weekly prices over 2004–2025 averaged 9.8% below their annual mean in January and 7.5% above it in June.

In the EIA’s annual state series, Illinois ranked 47th-cheapest of the 51 in 1970 and 8th-cheapest in 1981. From 2000 through 2014 its annual average ranged from 3.1¢ below to 7.7¢ above the U.S. average; from 2015 through 2024 it ranged from 7.0¢ to 12.1¢ below, ranking between 19th and 23rd. The highest annual average is $3.80, in 2022. Adjusted for inflation, the highest was 2011 (2012 was within a cent), at $4.96 in 2025 dollars, and the lowest 1998, at $1.08 ($2.14 in 2025 dollars).

Illinois ranked 47th-cheapest in 1970, when its average was $0.38. By 1980 the average was $1.23 and the rank was 21st-cheapest. The 1990 average of $1.17 was 24th-cheapest (tied), and the 2000 average of $1.52 was 31st-cheapest. In 2010 the average was $2.72, 22nd-cheapest, and in 2020 it was $2.04, 19th-cheapest (tied).

In 2024 Illinois stood 23rd-cheapest, which is also 29th-most-expensive, at $3.18. The EIA's rank 1 means the cheapest of the 50 states and D.C. The 8th-cheapest in 1981 is the cheapest ranking Illinois held in any year from 1970 to 2024, and the 47th-cheapest (5th-most-expensive) in 1970 is its least favourable.

Measured against the U.S., Illinois averaged below the national figure in 29 of 55 years and above it in 25 of 55. The widest gap above was 7.7¢ in 2001. The widest gap below was 12.1¢ in 2020. In 2024 the U.S. average was $3.29 and Illinois averaged 10.9¢ below it.

The EIA figures cover all grades of motor gasoline with taxes included. The EIA estimates each year after 2010 from the change in the state's region, so the moves since 2011 are the region's moves. On that basis the annual average rose 41.2% in 2021, and in 2015 it fell 28.2%. The 2024 average equals $3.26 in 2025 dollars, and from 2014 to 2024 the constant-dollar figure fell 27.2%.