Spearfish to Harrisburg is 402.7 miles and takes about 6h 32m via I 90 and I 29, with a fuel budget near $63 and enough daylight to finish in a day. This drive stays within South Dakota, traversing the Great Plains region for its entirety. Expect a straightforward, mostly highway experience that is ideal for a single-day trip. It’s a good option if you're looking for an efficient way to cover ground without much complexity.
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
201.3 miles from Spearfish, SD
A natural place for your longest stop of the day
, about 3h 15m into the drive
.
Main Roads
Road
Distance
Duration
I 90
383.9 mi
6h 5m
I 29
12.2 mi
13m
273rd Street
3.5 mi
6m
West Willow Street
1.6 mi
2m
East Jackson Boulevard
0.5 mi
1m
North Main Street
<0.1 mi
<1m
East Willow Street
—
—
Some road-level metrics are being recalculated.
Longest stretch:
I 90
— 383.9 mi, about 6h 5m
Turn-by-Turn Driving Directions
Step-by-step road directions between Spearfish, SD and Harrisburg, 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
338 mi·5 hr 19 min·I 90; US 14; US 16 Truck; SD 79
9
Take the exit
0.4 mi·57 sec
10
Merge onto I 29
12 mi·13 min·I 29
Use the straight / slight right lanes.
11
Take the exit
0.3 mi·41 sec
12
Turn left onto CR 110
3.5 mi·6 min·273rd Street
13
Continue on CR 110
1.6 mi·2 min·West Willow Street
14
Arrive at destination
CR 110
Trip Plan
To make the most of this 6h 32m drive, aim to depart Spearfish early in the morning. This allows you to cover the longest stretch of 383.9 miles on I 90 with minimal traffic. With a fuel cost estimated at $63, plan for one main fuel stop. Since this route is manageable in a single day, you have flexibility; however, staying on schedule is key to arriving in Harrisburg before evening. Keep an eye out for the transition from I 29 to 273rd Street, as this marks the beginning of your surface road driving.
Morning Departure
Start early — leave by 6-7 AM to arrive at a reasonable hour.
Evening Departure
This is a long drive — plan for a morning departure or consider splitting it into two days.
You can normally do this drive in one day.
Plan roughly 1 meaningful break for fuel, food, and rest.
The halfway point lands around 201.3 miles from Spearfish, SD, or about 3h 15m into the drive.
The longest continuous stretch on this route runs about 383.9 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 89 miles or 1h 29m in
Use this first pause for coffee, a restroom break, and a quick traffic check ahead.
Halfway reset
Around 201.3 miles or 3h 15m in
This is the best place for your longest stop, a real meal, and a full fuel check.
Final approach
Final hour starts around 5h 28m
Traffic, exits, and arrival timing usually matter more near Harrisburg, 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 402.7 miles and 6h 32m.
Your first comfortable stop window is around 89 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 383.9 miles.
Where to Stop
Rest stops, refuel points, and overnight suggestions along this route.
Place data sourced from public business listings. Hours and availability may vary.
Heads-up: tricky spots
5 of 8
5 decision points cluster between mile 0 and 397.7 — GPS handles the exact turns, but know they're coming. Your lane choice matters more than the turn itself.
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
5
385.2 mi into trip|~6h 9m in|I 29
Merge onto I 29
Merge point - match speed before joining. Lane positioning matters here
Use the straight / slight right lanes.
4
397.7 mi into trip|~6h 23m in|CR 110 / 273rd Street
Turn left onto CR 110 / 273rd Street
Navigation decision point
Fuel & Cost
Regular Gas
$62.96 one way
$125.92 round trip
$3.97/gal25.4 MPG avg141 kg CO2
Fuel Type
$/gal
One Way
Round Trip
midgrade
$4.36
$69.12
$138.25
premium
$4.89
$77.50
$154.99
diesel
$5.61
$88.91
$177.82
No toll roads detected on this route.
Estimated Trip Cost (one way, 1 person)
Fuel
$63
Meals
$25–$50
Total
$88–$113
Rough estimate based on US averages. Hotel $80–$140/night, meals $25–$50/day.
Estimated CO2 emission: 140.9 kg one way.
Prices: EIA weekly data, 2026-04-13.
Driving Electric?
About $42 in charging
· 1 stop
· 67% less CO2
Vehicle Type
kWh
Stops
DC Fast
Home Charge
Average EV
120.8
1
$42.28
$19.33
Efficient EV
100.7
1
$35.24
$16.11
EV Truck/SUV
161.1
2
$56.38
$25.77
Gas CO2
141 kg
EV CO2
47 kg (67% less)
Plan for 1 charging stop. A 30-minute DC fast charge mid-route should be enough to complete the trip comfortably.
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.
Forecast as of Apr 20, 2026
Origin
Spearfish, SD
Late night
in Spearfish on Tuesday
Local time
4:50 AM
MDT
Current temp
48°F
Unavailable
Live forecast
Destination
Harrisburg, SD
Late night
in Harrisburg on Tuesday
Local time
5:50 AM
CDT
Current temp
58°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
10 degrees warmer at arrival
A meaningful temperature swing is a good cue to rethink layers, water, and how soon you want to arrive.
Road read
6h 32m on the road
Start early — leave by 6-7 AM to arrive at a reasonable hour.
Weather data from the National Weather Service. Conditions may change; check closer to your travel date.
National Parks Near This Route
Worth a detour if your schedule allows.
Mount Rushmore National Memorial
National Memorial
Majestic figures of George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln, surrounded by the beauty of the Black Hills of South Dakota, tell the story of the birth, growth, devel...
20 mi from route
~49 min detour
Free
near mile 41.7
The rugged beauty of the Badlands draws visitors from around the world. These striking geologic deposits contain one of the world’s richest fossil beds. Ancient horses and rhinos once roamed here. The...
24 mi from route
~61 min detour
$30
near mile 97.2
Park data from the National Park Service API. Alerts update every 2 hours.
More Details
What kind of drive is this?
You'll be on highways for about 98% of this 402.7-mile trip. The bulk of your driving, a continuous stretch of 383.9 miles, will be on I 90. You'll transition to surface roads near the end of your trip, specifically on 273rd Street. Given the high highway percentage, anticipate a consistent cruising speed with frequent, though generally well-spaced, exits.
98% highway — fuel and pacing are the main things to plan.
14 navigation steps total — most of the decisions cluster near the start and finish.
Longest single stretch: 383.9 mi on I 90.
How Hard Is This Drive?
4/10
This is a straightforward highway drive that stays mostly on I 90 and I 29. 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 Effort4/10
Easy - simple navigation with a manageable amount of wheel time
Balances navigation complexity with total wheel time.
The route itself is not hard, but at 6h 32m, endurance matters. Plan breaks every 2-3 hours. The 8 decision points are all manageable with basic attention.
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.
Who Is This Route For?
Weekend Trip
Doable as a same-day drive at 6h 32m. Total distance: 402.7 miles.
Family Friendly
Moderate complexity with 1 natural rest stops along the way.
The longest stretch is about 383.9 miles on I 90. The full list of main roads is in the Roads section above.
Yes — we found about 25 rest areas or service plazas within a short detour of the route (from OpenStreetMap). See the Rest Stops tab under Nearby Places for locations and mile markers. Plan to stretch, use the bathroom, and top off fluids every 2–3 hours on longer drives.
It helps. This is a long drive, so arriving tired and in the dark compounds. If the last hour of the trip is on surface roads or mountain grades, aim to arrive at Harrisburg, SD before sunset when you can. Check the Trip Plan for departure windows that land you in daylight.
Only with planning. This is a long drive for kids — consider splitting it into two days rather than pushing through. Plan at least 1 meaningful breaks. There are 25 rest areas along the route for bathroom stops.
Mostly yes along the main roads, but rural stretches through SD can have sparse or no coverage. Before you leave, download offline Google Maps or Apple Maps for the route, and consider downloading music or podcasts instead of streaming. If you depend on data for navigation, keep a paper backup of the turn-by-turn directions.
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.
Yes — Mount Rushmore National Memorial and Badlands National Park. See the National Parks section for detour distances and tips on detours.
Not recommended in a single day. At 6.5 hours each way, a round trip means 13.1 hours of driving — that is an unsafe level of fatigue for most drivers. Plan at least one night at Harrisburg, SD before the return drive.
