Compiled and reviewed by the US Trip Planner planning team at COD Solutions Oy · Last reviewed Apr 19, 2026 · Editorial standards
Drive Time
4h 20m
Distance
257.7 mi
415 km
Drive Score
8/10
Great drive
Same Day?
Yes, doable
Fuel Cost
$40
one way
EV Charging
Unknown
Estimated drive times based on typical traffic patterns. Actual times may vary with weather, construction, and real-time conditions.
Spearfish, SD
Wikimedia Commons
Fort Thompson, SD
Esteban Carriazo
Spearfish to Fort Thompson is 257.7 miles and takes about 4h 20m via I 90 and SD 47, with a fuel budget near $40 and enough daylight to finish in a day. This drive stays entirely within the Great Plains region, offering a straightforward journey across South Dakota. You'll primarily be on interstate highway, making it a practical choice for getting from point A to point B efficiently. Consider this route if you're looking for a direct path with minimal detours, suitable for a single-day trip.
Trip Pace
Same-day drive is realistic
A same-day return is possible, but it will make for a full day on the road.
Break Rhythm
1 planned break
Plan on a short reset every 3 to 4 hours to stay fresh behind the wheel.
Midpoint
128.9 miles from Spearfish, SD
A natural place for your longest stop of the day , about 2h 7m into the drive .
| Road | Distance | Duration |
|---|---|---|
| I 90 | 236.2 mi | 3h 46m |
| SD 47 | 19.4 mi | 28m |
| SD 248 | 0.8 mi | 1m |
| East Jackson Boulevard | 0.5 mi | 1m |
| North Main Street | <0.1 mi | <1m |
| BIA Route 4 | <0.1 mi | <1m |
Step-by-step road directions between Spearfish, SD and Fort Thompson, SD.
Start on I 90 Business
Continue on I 90 Business
Turn right onto East Jackson Boulevard
Take the ramp
Merge onto I 90; US 14; US 85
Continue on I 90; US 14; SD 34
Continue on I 90; US 14; SD 79
Continue on I 90; US 14; US 16 Truck; SD 79
Take the exit
Turn left onto SD 248
Continue on SD 47
Turn sharp right onto BIA 4
Arrive at destination
Given the 4h 20m duration, you can comfortably complete this trip in one day. Aim to depart in the morning to allow for any unforeseen delays and to maximize daylight. With only one recommended stop, plan your fuel and rest breaks strategically, perhaps around the halfway point. The longest stretch without a significant change in road is over 236 miles on I 90, so ensure you have enough fuel before embarking on that segment to avoid any last-minute searches for a gas station.
Morning Departure
An early start around 7-8 AM gets you there with plenty of daylight left.
Evening Departure
A late afternoon start means arriving after dark. Morning is better.
This is a comfortable same-day trip.
Departure
Before you leave
Start with fuel, water, and navigation already sorted so the first hour feels easy.
First stop
Around 57 miles or 58m in
Use this first pause for coffee, a restroom break, and a quick traffic check ahead.
Halfway reset
Around 128.9 miles or 2h 7m in
This is the best place for your longest stop, a real meal, and a full fuel check.
Final approach
Final hour starts around 3h 25m
Traffic, exits, and arrival timing usually matter more near Fort Thompson, SD than in the middle of the route.
Open the route before leaving Spearfish, SD so your first major turns are already loaded.
Leave with enough water and a charging cable within reach, not packed away.
Check your fuel range against the first long segment, especially if you are starting outside city service areas.
Day 1
Settle into the route from Spearfish, SD
This is one driving day of about 257.7 miles and 4h 20m.
Rest stops, refuel points, and overnight suggestions along this route.
Mid-route town
Meal stop
129 mi into the route
Best for: Lunch, fuel, and a longer reset
This sits close to the middle of the route, so it works well for the longest stop of the day.
A short stop after about 57 miles helps settle the day before fatigue starts building.
The midpoint is around 128.9 miles from Spearfish, SD, which is a good place for a longer meal and fuel stop.
Before the longest stretch
Fuel checkTop up before I 90 if your tank is already low. That segment runs about 236.2 miles.
These stop ideas are pacing suggestions — the exact town or exit can change with traffic, hotel plans, and fuel range.
5 decision points cluster between mile 0 and 257.7 — GPS handles the exact turns, but know they're coming. Your lane choice matters more than the turn itself.
Continue onto I 90 Business / North Main Street
Navigation decision point
Turn right onto East Jackson Boulevard
Navigation decision point
Take the ramp toward I 90 East, US 85 South
Multiple destination signs - pick the right one
Turn left onto SD 248
Navigation decision point
Turn sharp right onto BIA 4 / BIA Route 4
Sharp turn - reduce speed on approach
Regular Gas
$40.29 one way
$80.58 round trip
| Fuel Type | $/gal | One Way | Round Trip |
|---|---|---|---|
| midgrade | $4.36 | $44.24 | $88.47 |
| premium | $4.89 | $49.59 | $99.18 |
| diesel | $5.61 | $56.90 | $113.79 |
No toll roads detected on this route.
Estimated Trip Cost (one way, 1 person)
Fuel
$40
Meals
$25–$50
Total
$65–$90
Rough estimate based on US averages. Hotel $80–$140/night, meals $25–$50/day.
Estimated CO2 emission: 90.2 kg one way. Prices: EIA weekly data, 2026-04-13.
Driving Electric?
About $27 in charging · 0 stops · 67% less CO2
| Vehicle Type | kWh | Stops | DC Fast | Home Charge |
|---|---|---|---|---|
| Average EV | 77.3 | 0 | $27.06 | $12.37 |
| Efficient EV | 64.4 | 0 | $22.55 | $10.31 |
| EV Truck/SUV | 103.1 | 1 | $36.08 | $16.49 |
Gas CO2
90 kg
EV CO2
30 kg (67% less)
Plan for 0 charging stops, roughly every 270 miles. Allow 25-40 minutes per stop at a DC fast charger.
DC fast charging avg $0.35/kWh. Home charging avg $0.16/kWh. US grid CO2: 0.39 kg/kWh.
Current conditions at both ends of the drive.
Origin
Evening in Spearfish on Saturday
Local time
7:10 PM
MDT
Current temp
26°F
Partly Cloudy
Red Flag Warning
Red Flag Warning issued April 18 at 1:10AM MDT until April 18 at 8:00PM MDT by NWS Rapid City SD
Destination
Evening in Fort Thompson on Saturday
Local time
8:10 PM
CDT
Current temp
52°F
Sunny
Red Flag Warning
Red Flag Warning issued April 18 at 1:10AM MDT until April 18 at 8:00PM MDT by NWS Rapid City SD
Seasonal Notes
Summer travel usually means heavier construction, hotter rest stops, and busier weekend traffic around major cities.
Winter travel shortens daylight, so a route that looks manageable on paper can feel much longer after dark.
Holiday weekends tend to make both departure and arrival windows slower than the raw route time suggests.
Time zone
The destination clock does not match departure time, so double-check hotel check-in windows and late arrival plans.
Temperature spread
A meaningful temperature swing is a good cue to rethink layers, water, and how soon you want to arrive.
Road read
An early start around 7-8 AM gets you there with plenty of daylight left.
Weather data from the National Weather Service. Conditions may change; check closer to your travel date.
This is a highway-focused drive, with 100% of the journey taking place on major roads. You'll experience a significant stretch of 236.2 miles on I 90, which means consistent speed limits and a predictable driving experience. The route transitions to SD 47 and SD 248, but these are also well-maintained highways. Expect a smooth, uninterrupted drive for the most part, ideal for covering ground quickly across the South Dakota landscape.
This is a straightforward highway drive that stays mostly on I 90 and SD 47. There are only a few real navigation decisions along the way. The trickiest moment comes early in the drive near I 90 Business / North Main Street.
Easy - simple navigation with a manageable amount of wheel time
Balances navigation complexity with total wheel time.
This is a straightforward 4h 20m drive. You will face about 7 decision points, but nothing that requires special attention if you follow navigation.
Where does it get tricky?
The main spots that need attention: near the start (I 90 Business / North Main Street): Navigation decision point; near the start (East Jackson Boulevard): Navigation decision point; at 0.6 miles: Multiple destination signs - pick the right one.
Weekend Trip
Doable as a same-day drive at 4h 20m. Total distance: 257.7 miles.
Family Friendly
Moderate complexity with 1 natural rest stops along the way.
Solo Traveler
4h 20m drive, comfortable solo distance.
First-Time Driver
Mostly highway driving (100%). Straightforward navigation.
Compiled by the US Trip Planner planning team at COD Solutions Oy from open government datasets — OSRM over OpenStreetMap for geometry, and EIA for fuel prices. See our methodology for refresh cadence and limitations.
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