Illinois Gas Prices and Why They Are What They Are
Prices as of July 06, 2026, per AAA · Updated July 06, 2026
As of July 06, 2026, regular gasoline in Illinois averages $3.99/gallon (the 10th-highest in the U.S.), per AAA — 0.16 above the national average of $3.83. Diesel averages $4.91. State fuel taxes and fees add 66.4¢/gallon on top of the 18.4¢ federal excise.
Where the $3.99 goes
| Component | $/gallon | Share | Source |
|---|---|---|---|
| Crude oil (national cost, WTI June 2026) | 2.04 | 51% | EIA |
| Federal + Illinois fuel taxes (18.4¢ + 66.4¢) | 0.85 | 21% | Tax Foundation |
| Refining, distribution, margins & embedded program costs (residual) | 1.11 | 28% | computed |
Crude oil costs every state's refiners roughly the same, so Illinois's position comes from the tax line and the residual: refining capacity and logistics, fuel-specification requirements, and any carbon or clean-fuel program costs embedded in the pump price.
State policies that show up at the pump
| Policy | Detail |
|---|---|
| State sales tax on fuel | Yes (6.25%) |
| Cap-and-trade on motor fuel | No |
| Low Carbon Fuel Standard | No (proposed) |
| Federal RFG areas | Yes (Chicago metro) |
| Refinery count | 4 active |
| Pipeline access | Yes (Midwest hub) |
State government control
| Control today | Unified Democratic (Governor + House + Senate, all D) |
| Years of unified Democratic control, 2001–2025 | 19 |
| Years of unified Republican control | 0 |
| Years of divided government | 6 |
Fuel-tax levels and fuel-specification programs are set by legislatures and governors; the national comparison shows average prices and taxes grouped by state control.
Compare: all states ranked · Illinois electricity rates · gasoline prices by country
Sources: AAA (pump prices, updated daily; the industry-standard 50-state series), Tax Foundation (2026 state fuel taxes), EIA (WTI crude). The residual is computed, not reported. See methodology.