For 2017, the highest average gas prices in the nation were in the west coast states plus Alaska and Hawaii. Hawaii had the highest average at $3.09 per gallon, followed by California at $3.00, and Alaska at $2.89. Gas prices were generally more expensive in the north and northeast than in the southern states. Factors contributing to price variance include distribution cost, taxes, and octane content. South Carolina had the lowest average gas price at $2.13 per gallon while the national average was $2.40 per gallon. The price of gasoline can vary greatly among individual stations across each state.