Gasoline prices reached what is believed to be an all-time high in Decatur on Wednesday, when prices jumped some 30 cents a gallon to $4.15 and $4.16.
Similar prices were seen in Fort Wayne.
Meanwhile, most experts expect higher prices as we move toward the peak summer driving season.
Prices rose to a nationwide average of $3.90 per gallon on Monday, having gone up 17 cents so far this month.
The national average peaked last year in early May at $3.98 per gallon. The record high of $4.11 was set in July 2008.