Origin
Spearfish, SD
Late night in Spearfish on Saturday
Local time
4:18 AM
MDT
Current temp
73°F
Unavailable
Live forecast
Trip from Spearfish, SD to Fort Thompson, SD
Compiled and reviewed by the Trip.ovh planning team at COD Solutions Oy · Last reviewed Apr 18, 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
Best Time to Leave
4 AM
4h 7m
★
6 AM
4h 21m
8 AM
4h 47m
10 AM
4h 30m
12 PM
4h 27m
3 PM
4h 31m
5 PM
4h 46m
8 PM
4h 13m
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
Trip Overview
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 .
Who Is This Route For?
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.
Drive Character
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.
Most of the miles stay on highways, which makes pacing and fuel planning easier than turn-by-turn city driving.
There are about 13 navigation steps in the underlying route data, so the final approach matters more than the middle miles.
I 90 is the longest continuous segment at about 236.2 miles.
How Hard Is This Drive?
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.
Driving Effort
3/10
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.
Critical Maneuvers
5 of 7 key pointsThese are the spots where you need to pay the most attention. Preview them before you drive.
3
0 mi into trip
|
~0m in
|
I 90 Business / North Main Street
Continue onto I 90 Business / North Main Street
Navigation decision point
4
0 mi into trip
|
~0m in
|
East Jackson Boulevard
Turn right onto East Jackson Boulevard
Navigation decision point
5
0.6 mi into trip
|
~2m in
Take the ramp toward I 90 East, US 85 South
Multiple destination signs - pick the right one
Toward I 90 East, US 85 South
4
237.4 mi into trip
|
~3h 50m in
|
SD 248
Turn left onto SD 248
Navigation decision point
5
257.7 mi into trip
|
~4h 20m in
|
BIA 4 / BIA Route 4
Turn sharp right onto BIA 4 / BIA Route 4
Sharp turn - reduce speed on approach
Main Roads
| 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 |
Longest stretch:
I 90
— 236.2 mi, about 3h 46m
Turn-by-Turn Driving Directions
Step-by-step road directions between Spearfish, SD and Fort Thompson, SD.
1
Start on I 90 Business
85 ft
·
30 sec
·
North Main Street
2
Continue on I 90 Business
166 ft
·
9 sec
·
North Main Street
3
Turn right onto East Jackson Boulevard
0.5 mi
·
1 min
·
East Jackson Boulevard
4
Take the ramp
0.3 mi
·
37 sec
Toward I 90 East, US 85 South
5
Merge onto I 90; US 14; US 85
14 mi
·
14 min
·
I 90; US 14; US 85
6
Continue on I 90; US 14; SD 34
7.6 mi
·
7 min
·
I 90; US 14; SD 34
7
Continue on I 90; US 14; SD 79
24 mi
·
24 min
·
I 90; US 14; SD 79
8
Continue on I 90; US 14; US 16 Truck; SD 79
191 mi
·
3 hr 1 min
·
I 90; US 14; US 16 Truck; SD 79
9
Take the exit
0.3 mi
·
50 sec
10
Turn left onto SD 248
0.8 mi
·
1 min
·
SD 248
11
Continue on SD 47
19 mi
·
28 min
·
SD 47
12
Turn sharp right onto BIA 4
65 ft
·
1 sec
·
BIA Route 4
13
Arrive at destination
BIA 4
Trip Plan
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.
You can normally do this drive in one day.
Plan roughly 1 meaningful break for fuel, food, and rest.
The halfway point lands around 128.9 miles from Spearfish, SD, or about 2h 7m into the drive.
The longest continuous stretch on this route runs about 236.2 miles.
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.
Before You Leave
+
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.
Your first comfortable stop window is around 57 miles from Spearfish, SD.
This route can stay practical as a one-day drive if traffic stays reasonable.
Plan about 1 real break rather than only quick fuel stops.
The longest stretch is on I 90 for about 236.2 miles.
Where to Stop
Rest stops, refuel points, and overnight suggestions along this route.
Halfway Point
Midpoint
About 128.9 mi from Spearfish, SD · 2h 7m into the drive
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.
Pacing Suggestions
Fuel and coffee
A short stop after about 57 miles helps settle the day before fatigue starts building.
Meal break
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.
Arriving in Fort Thompson, SD
The final approach into Fort Thompson, SD usually feels slower than the middle of the drive, so avoid planning your tightest schedule at the very end.
Try to arrive with enough fuel left to skip an immediate station stop unless you already know the area around Fort Thompson, SD.
After long uninterrupted mileage, take five minutes before the last urban segment to reset and refocus on exits, merges, and city traffic.
These stop ideas are pacing suggestions — the exact town or exit can change with traffic, hotel plans, and fuel range.
Fuel & Cost
Regular Gas
$40.29 one way
$80.58 round trip
$3.97/gal
25.4 MPG avg
90 kg CO2
| 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.
Travel Intel
Current conditions at both ends of the drive.
Destination
Fort Thompson, SD
Late night in Fort Thompson on Saturday
Local time
5:18 AM
CDT
Current temp
47°F
Unavailable
Live forecast
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
1 hour later
The destination clock does not match departure time, so double-check hotel check-in windows and late arrival plans.
Temperature spread
26 degrees cooler at arrival
A meaningful temperature swing is a good cue to rethink layers, water, and how soon you want to arrive.
Road read
4h 20m on the road
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.
Frequently Asked Questions
The drive from Spearfish, SD to Fort Thompson, SD covers 257.7 miles and takes about 4h 20m without stops. Add 15-30 minutes for a fuel or rest stop on longer drives.
The main roads are I 90, SD 47, SD 248. Most of the drive stays on highways, so watch for ramps and exits.
This is a comfortable same-day trip.
The midpoint is about 128.9 miles from Spearfish, SD. Look for rest areas, gas stations, or food options near the halfway mark.
At current regular gas prices, expect to spend about $40.29 one way. This estimate uses 25.4 MPG — your actual cost will vary with your vehicle's fuel efficiency and current gas prices.
An early start around 7-8 AM gets you there with plenty of daylight left. A late afternoon start means arriving after dark. Morning is better.
Plan about 1 meaningful break for fuel, food, or rest. Plan on a short reset every 3 to 4 hours to stay fresh behind the wheel.
This is a straightforward 4h 20m drive. You will face about 7 decision points, but nothing that requires special attention if you follow navigation.
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.
The route from Spearfish, SD to Fort Thompson, SD does not surface many named destination signs beyond the main corridor.
How this page is built
Compiled by the Trip.ovh 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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