Fuel Prices in South Dakota: What Drivers Pay at the Pump
South Dakota sits in the heart of the northern Great Plains, and its fuel prices reflect a familiar mix of taxes, distance from refineries, and a sparse population spread across long highways. As of the latest data, the average price for a gallon of regular unleaded in the state is $3.737. Midgrade runs about $3.964, premium reaches $4.461, and diesel — the lifeblood of the state's farming and trucking economy — averages $4.329 per gallon.
That regular price comes in below the US national average of $3.867, which is typical for the Midwest. States in this region generally enjoy cheaper gasoline than the coasts because they sit closer to inland refining hubs and pipeline corridors fed by Midcontinent and Canadian crude.
What Drives South Dakota's Pump Prices
Three forces shape what you pay in Sioux Falls, Rapid City, or any small town along I-90. The first is taxes. South Dakota levies a state motor fuel excise tax of 28 cents per gallon on gasoline and 28 cents on diesel (with a slightly higher rate for certain blends), layered on top of the federal tax of 18.4 cents for gasoline and 24.4 cents for diesel. Combined, taxes account for roughly 46 to 53 cents of every gallon — moderate by national standards and well below high-tax states.
The second factor is logistics. South Dakota has no major oil refineries of its own. Most of its gasoline and diesel arrives by pipeline and truck from refineries in the broader Midcontinent region, including facilities in neighboring states and the heavy crude flows tied to Canadian and Bakken production just to the north and west. The state's low population density means fewer high-volume stations to spread fixed costs across, which can nudge retail margins higher in remote areas.
The third is seasonality and crop economics. Diesel demand spikes during planting and harvest, and ethanol — produced abundantly from South Dakota corn — is blended into most regular gasoline sold here. The state is one of the country's leading ethanol producers, and that domestic blendstock helps keep regular grade competitive. The premium-over-regular spread of about $0.72 is wider than in many states, reflecting lower premium volumes across rural markets.
How South Dakota Compares to Other States
Because the US prices fuel entirely in dollars per gallon, comparisons across states are straightforward — there is no currency conversion to worry about. South Dakota's regular price tends to track other agricultural Plains states and stays cheaper than the national figure. Coastal and Mid-Atlantic states often run higher: you can see this by comparing with Maryland, Virginia, or Delaware, where higher demand density and different tax structures apply. Sun Belt markets like Florida behave differently again, with seasonal tourism swings.
For a state with only a handful of metro areas, prices stay remarkably uniform. Drivers should still expect to pay a little more on remote stretches of highway and a little less in the competitive Sioux Falls and Rapid City corridors.
FAQ
Why is gas cheaper in South Dakota than the US average?
South Dakota benefits from its inland location near Midcontinent and Canadian crude supplies, moderate state fuel taxes around 28 cents per gallon, and abundant locally produced ethanol blended into gasoline. At $3.737 for regular versus the national $3.867, the state runs below average — a common pattern across the Midwest.
How much is diesel in South Dakota right now?
Diesel averages about $4.329 per gallon in South Dakota. Diesel often costs more than gasoline here because of strong demand from agriculture and long-haul trucking, plus a federal diesel tax that is higher than the gasoline rate. Prices climb further during planting and harvest seasons.
Does South Dakota have its own oil refineries?
No. South Dakota has no major refineries and imports nearly all of its finished gasoline and diesel by pipeline and truck from refining hubs in surrounding states. The state does, however, produce large volumes of corn-based ethanol that is blended into most of its regular-grade fuel.