Gas prices in Illinois: Midwest average and state gas tax
There's no official weekly average just for Illinois. What there is: the Midwest regional average, which the state is part of, at $4.39 for regular this week (September 21, 2026). That's −9.2¢ versus the whole country. Taxes are a big part of the story: Illinois's state gas tax and fees total 71.7¢ per gallon (2nd of 51, highest first), and diesel carries 79.2¢. Since January 2015, the gasoline rate has moved +32.6¢.
The quick take
Crossing a state line can change the tax you pay: next door to Illinois, rates run from 26.4¢ in Kentucky to 64.5¢ in Indiana.
Cities
Regular gas, weekly average · Midwest
September 30, 2024: $3.105 · September 21, 2026: $4.386 · min $2.585 · max $4.405
The state's gas tax since 2015
| Rate as of | Gasoline | Diesel |
|---|---|---|
| Jul 2026 | 71.7¢ | 79.2¢ |
| Jan 2026 | 66.4¢ | 73.9¢ |
| Jul 2025 | 66.4¢ | 73.9¢ |
| Jan 2025 | 66.1¢ | 73.6¢ |
| Jul 2024 | 67.1¢ | 74.6¢ |
| Jan 2024 | 66.5¢ | 74.0¢ |
| Jul 2023 | 66.5¢ | 74.0¢ |
| Jan 2023 | 67.4¢ | 74.9¢ |
| Jul 2022 | 63.3¢ | 70.8¢ |
| Jan 2022 | 58.3¢ | 65.8¢ |
| Jul 2021 | 55.3¢ | 62.8¢ |
| Jul 2020 | 51.8¢ | 59.3¢ |
| Jan 2020 | 53.1¢ | 60.6¢ |
| Jul 2019 | 54.1¢ | 61.6¢ |
| Jan 2019 | 36.1¢ | 38.6¢ |
| Jul 2018 | 35.1¢ | 37.6¢ |
| Jan 2018 | 34.1¢ | 36.6¢ |
| Jul 2017 | 33.1¢ | 35.6¢ |
| Jan 2017 | 32.1¢ | 34.6¢ |
| Jul 2016 | 33.1¢ | 35.6¢ |
| Jan 2016 | 33.1¢ | 35.6¢ |
| Jul 2015 | 34.1¢ | 36.6¢ |
| Jan 2015 | 39.1¢ | 41.6¢ |
Neighboring states
Iowa30.0¢Indiana64.5¢Kentucky26.4¢Missouri30.0¢Wisconsin32.9¢
Map
Region: Midwest · Gas tax by state · Diesel prices · U.S. average