How far is Spearfish, SD from Fort Thompson, SD?
The driving distance from Spearfish, SD to Fort Thompson, SD is about 257.7 miles (414.7 km), with a travel time of about 04h 20m by car.
- The straight-line flight distance is about 220.6 miles (355.1 km).
- For a round trip, plan for roughly 08h 41m of driving time before adding stops, traffic, or weather delays.
- A comfortable departure window is usually 6:00 AM to 8:00 AM MDT.
Reverse, save, or send this route
This drive is better planned with a longer stop or an overnight stay. Copy the route link, send it to another device, or print a clean version before you head out.
This drive is better planned with a longer stop or an overnight stay.
Flight Distance
Driving Distance
Gas Cost Calculator
Leave and Arrive Planner
Pick a departure time to see your estimated arrival and same-day return window.
Drive time stays fixed at 04h 20m.
An early departure helps you fit a real stop into the day without turning the return into a late-night drive.
You are leaving earlier than the recommended window, which gives you extra margin for breaks and traffic.
Halfway Point
A useful midpoint for breaks, coffee, or meeting in the middle.
Human settlement in United States of America
Route Weather Snapshot
Check the forecast at both ends before you head out.
Mostly Clear
Sunny
Driving Route Map
The map below follows the saved road route between Spearfish and Fort Thompson.
Turn-by-Turn Driving Directions
Step-by-step road directions between Spearfish and Fort Thompson.
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1
Start on North Main Street
26 m · 30 sec · North Main Street
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2
Continue on North Main Street
51 m · 10 sec · North Main Street
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3
Turn right onto East Jackson Boulevard
2777 ft · 2 min · East Jackson Boulevard
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4
Take the ramp right toward I 90 East, US 85 South
1555 ft · 38 sec
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5
Merge slight left
14.2 mi · 14 min
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6
Continue straight
7.6 mi · 8 min
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7
Continue straight
23.6 mi · 24 min
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8
Continue straight
190.8 mi · 3 hr 1 min
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9
Take the exit slight right
1789 ft · 51 sec
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10
Turn left
1.3 km · 1 min
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11
Continue straight
19.4 mi · 29 min
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12
Turn sharp right onto BIA Route 4
20 m · 2 sec · BIA Route 4
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13
Arrive at your destination
0 m · 1 sec · BIA Route 4
Car Route Details
A richer read on the saved driving route between Spearfish and Fort Thompson.
Highway-focused drive
Most of the mileage stays on named highways, so the important moments are ramps, exits, merges, and the final local approach.
I 90 East
Continue straight
191 mi · 03h 01m
Route Summary
A quick read on whether this route feels easy, ambitious, or worth planning around.
A longer out-and-back drive
This is still possible in one day, but it becomes a long driving day. Leaving early and planning your stop window matters more here.
Mostly Clear leaving Spearfish and Sunny near Fort Thompson.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Spearfish to Fort Thompson?
The road trip is about 257.7 miles (414.7 km) and usually takes 04h 20m in normal driving conditions.
Is this a same-day trip or an overnight route?
This is still possible in one day, but it becomes a long driving day. Leaving early and planning your stop window matters more here.
What is the halfway point on this route?
Weta is a useful midpoint, sitting about 128.6 miles from Spearfish and 129.1 miles from Fort Thompson.
How much longer is the road route than the straight-line distance?
The direct path is about 220.6 miles (355.1 km), while the road route adds roughly 37.1 extra miles because roads do not follow the straight air line.
When is the best time to leave for this route?
A good departure window is usually 6:00 AM to 8:00 AM MDT. If you want a more comfortable same-day return, try to leave by 8:18 AM MDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $34.28 one way or $68.56 round trip. Estimated CO2 is about 80.8 kg one way.
Do you cross a time zone on this route?
Yes. There is about a 1 hour time difference between Spearfish and Fort Thompson, so arrival and return times should be read in local time.
What should you check before leaving?
Before you leave, expect Mostly Clear around Spearfish and Sunny near Fort Thompson.
Flight Path Map
This map shows the direct air route between Spearfish and Fort Thompson. Straight-line distance: 220.62 mi (355.06 km).
#1 Spearfish
City in Lawrence County, South Dakota, United States
| Population | 11,900 |
| Coordinates | 44.4908200, -103.8593700 |
| Altitude | 1112 |
| Country | United States |
#2 Fort Thompson
Census-designated place in Buffalo County, South Dakota, United States
| Population | 1,282 |
| Coordinates | 44.0686000, -99.4378800 |
| Altitude | 439 |
| Country | United States |
End: Fort Thompson (-99.43788, 44.0686)
Estimated Travel Time
Distance: 415 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 08h 35m |
| 40 mph (64.37 km/h) | 06h 26m |
| 50 mph (80.47 km/h) | 05h 09m |
| 60 mph (96.56 km/h) | 04h 17m |
| 70 mph (112.65 km/h) | 03h 40m |
| 80 mph (129 km/h) | 03h 12m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $34.28 | $68.56 |
| Mid-grade | $4.25 | $38.66 | $77.32 |
| Premium | $4.65 | $42.30 | $84.61 |
| Diesel | $5.30 | $48.21 | $96.43 |
Assumes 8.3 L/100 km (about 28.3 MPG). CO2 is an estimate and varies by vehicle, fuel blend, traffic, and terrain.
Prices in South Dakota · Apr 16, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.