The U. S. on-highway diesel fuel price for the week of March 4, 2019 is an average of $3.076 per gallon. The price has been steadily rising over the past month. Every region in the country showed an increase from the previous week. The largest gap in price was between the Gulf Coast Region and California. In the Gulf Coast Region, the price was $2.870 per gallon. In contrast, California came in at $3.779 per gallon!