Spanning 285.9 miles across South Dakota, this trip connects Gregory to Spearfish in approximately 5 hours and 13 minutes. Because the route remains within the Great Plains, you can comfortably complete the journey in a single day, though you should budget about $43 for fuel. The path relies heavily on US Highway 18 and I-90 to move you efficiently across the state. Expect a straightforward drive that prioritizes speed and directness over winding scenic detours. Whether you are heading west for a vacation or a quick regional transit, this trip is manageable for most drivers without the need for an overnight stop.
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
142.9 miles from Gregory, SD
A natural place for your longest stop of the day
, about 2h 53m into the drive
.
Main Roads
Road
Distance
Duration
I 90
213.8 mi
3h 25m
307th Avenue
35.8 mi
51m
US Highway 18
34.4 mi
51m
East Jackson Boulevard
0.6 mi
1m
Park Avenue
0.4 mi
<1m
East 6th Street
0.2 mi
1m
North Main Street
<0.1 mi
<1m
Longest stretch:
I 90
— 213.8 mi, about 3h 25m
Turn-by-Turn Driving Directions
Step-by-step road directions between Gregory, SD and Spearfish, SD.
1
Start on East 6th Street
0.2 mi·1 min·East 6th Street
2
At end of road, turn left onto SD 47
0.4 mi·43 sec·Park Avenue
3
Turn right onto US 18
34 mi·51 min·US Highway 18
4
Turn right onto US 183; SD 44; SD 53
36 mi·51 min·307th Avenue
5
Take the ramp
0.3 mi·44 sec
6
Merge onto I 90
214 mi·3 hr 25 min·I 90
7
Take the exit
0.3 mi·43 sec
Toward Jackson Boulevard, Black Hills State University
8
Turn left onto East Jackson Boulevard
0.6 mi·1 min·East Jackson Boulevard
9
Turn left onto I 90 Business
149 ft·14 sec·North Main Street
10
Arrive at destination
I 90 Business
Trip Plan
To keep your drive smooth, aim to depart early in the morning to avoid fatigue during the long 213.8-mile interstate segment. With only one recommended stop planned, try to time your break to coincide with your fuel fill-up to maximize your time on the road. Since the route is highly dependent on I-90, keep a close watch on interstate traffic reports, as any delays here will significantly impact your 5-hour and 13-minute travel estimate. Take advantage of the flexibility this single-day itinerary offers, but ensure your vehicle is prepped for a sustained high-speed run across the plains. A practical tip: double-check your fuel levels before merging onto I-90, as this long stretch offers fewer exit opportunities than your initial local roads.
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 142.9 miles from Gregory, SD, or about 2h 53m into the drive.
The longest continuous stretch on this route runs about 213.8 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 63 miles or 1h 32m in
Use this first pause for coffee, a restroom break, and a quick traffic check ahead.
Halfway reset
Around 142.9 miles or 2h 53m in
This is the best place for your longest stop, a real meal, and a full fuel check.
Final approach
Final hour starts around 4h 22m
Traffic, exits, and arrival timing usually matter more near Spearfish, SD than in the middle of the route.
Before You Leave
+
Open the route before leaving Gregory, 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 Gregory, SD
This is one driving day of about 285.9 miles and 5h 13m.
Your first comfortable stop window is around 63 miles from Gregory, 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 213.8 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 7
5 decision points cluster between mile 0.2 and 284.9 — GPS handles the exact turns, but know they're coming. Your lane choice matters more than the turn itself.
5
0.2 mi into trip|~1m in|SD 47 / Park Avenue
At end of road, turn left onto SD 47 / Park Avenue
Navigation decision point
4
0.6 mi into trip|~1m in|US 18 / US Highway 18
Turn right onto US 18 / US Highway 18
Navigation decision point
4
35 mi into trip|~52m in|US 183; SD 44; SD 53 / 307th Avenue
Turn right onto US 183; SD 44; SD 53 / 307th Avenue
Navigation decision point
4
70.8 mi into trip|~1h 44m in
Take the ramp
Navigation decision point
5
284.9 mi into trip|~5h 10m in
Take the exit toward Jackson Boulevard, Black Hills State University
Exit ramp - move to the correct lane early. Multiple destination signs - pick the right one
Toward Jackson Boulevard, Black Hills State Uni...
Fuel & Cost
Regular Gas
$44.70 one way
$89.39 round trip
$3.97/gal25.4 MPG avg100 kg CO2
Fuel Type
$/gal
One Way
Round Trip
midgrade
$4.36
$49.08
$98.15
premium
$4.89
$55.02
$110.04
diesel
$5.61
$63.12
$126.25
No toll roads detected on this route.
Estimated Trip Cost (one way, 1 person)
Fuel
$45
Meals
$25–$50
Total
$70–$95
Rough estimate based on US averages. Hotel $80–$140/night, meals $25–$50/day.
Estimated CO2 emission: 100 kg one way.
Prices: EIA weekly data, 2026-04-13.
Driving Electric?
About $30 in charging
· 1 stop
· 67% less CO2
Vehicle Type
kWh
Stops
DC Fast
Home Charge
Average EV
85.8
1
$30.02
$13.72
Efficient EV
71.5
0
$25.02
$11.44
EV Truck/SUV
114.4
1
$40.03
$18.30
Gas CO2
100 kg
EV CO2
33 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 15, 2026
Origin
Gregory, SD
Evening
in Gregory on Saturday
Local time
8:06 PM
CDT
Current temp
47°F
Unavailable
Live forecast
Destination
Spearfish, SD
Evening
in Spearfish on Saturday
Local time
7:06 PM
MDT
Current temp
73°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 earlier
The destination clock does not match departure time, so double-check hotel check-in windows and late arrival plans.
Temperature spread
26 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
5h 13m 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.
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...
21 mi from route
~52 min detour
Free
near mile 236.6
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
~60 min detour
$30
near mile 187.3
Park data from the National Park Service API. Alerts update every 2 hours.
More Details
What kind of drive is this?
Expect a highway-focused experience, as 87% of your travel time will be spent on major routes. You will start on local roads like 307th Avenue before transitioning to the efficiency of US Highway 18 and eventually the interstate. The bulk of your journey involves a 213.8-mile stretch on I-90, which provides a consistent, high-speed pace for the majority of the trip. While the road is largely functional, the shift from regional highways to the interstate requires you to stay alert for changing traffic flow. Prepare for a steady, predictable ride that favors steady cruising over technical maneuvers.
87% highway — fuel and pacing are the main things to plan.
10 navigation steps total — most of the decisions cluster near the start and finish.
Longest single stretch: 213.8 mi on I 90.
How Hard Is This Drive?
3/10
This is a straightforward highway drive that stays mostly on I 90 and 307th Avenue. There are only a few real navigation decisions along the way. The trickiest moment comes around 0.2 miles in near SD 47 / Park Avenue.
Driving Effort3/10
Easy - simple navigation with a manageable amount of wheel time
Balances navigation complexity with total wheel time.
This is a straightforward 5h 13m 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: at 0.2 miles (SD 47 / Park Avenue): Navigation decision point; at 0.6 miles (US 18 / US Highway 18): Navigation decision point; at 35 miles (US 183; SD 44; SD 53 / 307th Avenue): Navigation decision point.
Elevation Profile
Gently rolling terrain
3,643 ft1,847 ft
Total Climb
1,898 ft
Total Descent
421 ft
Highest Point
3,643 ft
~285.9 mi in
Elevation Range
1,796 ft
Who Is This Route For?
Weekend Trip
Doable as a same-day drive at 5h 13m. Total distance: 285.9 miles.
Family Friendly
Moderate complexity with 1 natural rest stops along the way.
The longest stretch is about 213.8 miles on I 90. The full list of main roads is in the Roads section above.
We did not find dedicated rest areas on this route. For a drive this long, plan bathroom and stretch breaks around gas stations, fast-food stops, or small-town downtowns — check the Nearby Places section for options.
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. Dedicated rest areas are limited, so plan gas or food stops as your bathroom breaks.
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: at 0.2 miles (SD 47 / Park Avenue): Navigation decision point; at 0.6 miles (US 18 / US Highway 18): Navigation decision point; at 35 miles (US 183; SD 44; SD 53 / 307th Avenue): Navigation decision point.
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 5.2 hours each way, a round trip means 10.4 hours of driving — that is an unsafe level of fatigue for most drivers. Plan at least one night at Spearfish, SD before the return drive.
