Illinois state motor fuel tax was 19¢ per gallon before 2019. It doubled to 38¢ that year under the Rebuild Illinois plan and has risen with automatic CPI adjustments to the current 48.3¢ per gallon (the July 2026 hike is paused until January 2027).
That is 29.3¢ more per gallon, or roughly $143 extra per year for the average Illinois driver.