Gas prices in South Dakota: Midwest average and state gas tax

South Dakota falls in the EIA's Midwest region, and that regional number is the most precise public figure available: $4.39 a gallon for regular for the week of September 21, 2026, a +29.5¢ weekly change. Every gallon sold in South Dakota includes 48.4¢ in state and federal taxes: 30.0¢ goes to the state, 18.4¢ to Washington. That ranks the state 29th out of 51 for gas taxes.