The average national price for regular unleaded was $2.543 a gallon Tuesday, up from $2.215 a month ago, AAA said.
Analysts blame higher crude oil prices, greater demand and fears of shortages for the increase, The Washington Post reported.
Prices are highest in California, where regular averages $3.09 a gallon. In the San Francisco area, drivers pay an average $3.25.
"And prices are headed higher," John Townsend of AAA Mid-Atlantic said. "We're talking 15 cents to 20 cents higher by the end of the month."