How far is O'Fallon, MO from Sullivan, MO?
The driving distance from O'Fallon, MO to Sullivan, MO is about 62.4 miles (100.4 km), with a travel time of about 01h 25m by car.
- The straight-line flight distance is about 48.5 miles (78.1 km).
- For a round trip, plan for roughly 02h 51m of driving time before adding stops, traffic, or weather delays.
- A comfortable departure window is usually 8:00 AM to 10:00 AM CDT.
Reverse, save, or send this route
This route works well as a day trip with time at the destination. Copy the route link, send it to another device, or print a clean version before you head out.
This route works well as a day trip with time at the destination.
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 01h 25m.
A morning start gives you useful time at the destination and keeps the return out of the late evening.
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.
Census designated place
Route Weather Snapshot
Check the forecast at both ends before you head out.
Mostly Sunny
Mostly Sunny
Driving Route Map
The map below follows the saved road route between O'Fallon and Sullivan.
Turn-by-Turn Driving Directions
Step-by-step road directions between O'Fallon and Sullivan.
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1
Start on the route
8 m · 7 sec
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2
Turn left onto South Main Street
2865 ft · 1 min · South Main Street
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3
Continue straight
3.1 mi · 6 min
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4
Continue straight
3.4 mi · 5 min
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5
Take the ramp slight right toward I 64 East, US 40 East, US 61 South
1523 ft · 22 sec
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6
Merge slight left onto Avenue of the Saints
3.7 mi · 5 min · Avenue of the Saints
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7
Take the exit slight right toward Chesterfield Airport Road
2700 ft · 58 sec
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8
Continue on Chesterfield Airport Road
110 m · 7 sec · Chesterfield Airport Road
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9
Turn right onto Olive Street Road
64 m · 5 sec
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10
Turn right onto Olive Street Road
1.5 km · 2 min · Olive Street Road
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11
Continue on North Eatherton Road
2.4 mi · 5 min · North Eatherton Road
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12
Enter the roundabout and take exit 2 toward the route
21 m · 1 sec
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13
Exit the roundabout
4.3 mi · 7 min
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14
Enter the roundabout and take exit 2 toward the route
29 m · 2 sec
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15
Exit the roundabout
2098 ft · 45 sec
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16
Enter the roundabout and take exit 2 toward MO 100 West: Gray Summit
23 m · 2 sec
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17
Exit the roundabout onto MO 100 West: Gray Summit
1202 ft · 33 sec
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18
Merge slight left
13.3 mi · 19 min
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19
Take the exit slight right toward I 44 West, US 50 West: St. Clair
1157 ft · 14 sec
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20
Merge slight left
27.1 mi · 29 min
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21
Take the exit slight right toward MO 185 South, MO AF: Sullivan, Potosi
983 ft · 32 sec
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22
Turn left
1427 ft · 33 sec
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23
Turn right onto East Springfield Road
1.3 km · 2 min · East Springfield Road
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24
Turn left onto North Clark Street
1773 ft · 52 sec · North Clark Street
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25
At the end of the road, turn right onto West Main Street
629 ft · 21 sec · West Main Street
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26
Turn left onto Hughes Ford Road
36 m · 5 sec · Hughes Ford Road
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27
Turn left onto West Washington Street
103 m · 11 sec · West Washington Street
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28
Turn right
17 m · 4 sec
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29
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between O'Fallon and Sullivan.
Turn-heavy local drive
The route has frequent decision points for its length, so lane choice and turn timing will matter more than cruising speed.
I 44 West
Merge slight left
27.1 mi · 00h 29m
Route Summary
A quick read on whether this route feels easy, ambitious, or worth planning around.
A comfortable day-trip route
This route works well as a day trip. You can leave in the morning, spend meaningful time at the destination, and still return the same day.
Mostly Sunny leaving O'Fallon and Mostly Sunny near Sullivan.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from O'Fallon to Sullivan?
The road trip is about 62.4 miles (100.4 km) and usually takes 01h 25m in normal driving conditions.
Is this a same-day trip or an overnight route?
This route works well as a day trip. You can leave in the morning, spend meaningful time at the destination, and still return the same day.
What is the halfway point on this route?
Gray Summit is a useful midpoint, sitting about 31.2 miles from O'Fallon and 31.2 miles from Sullivan.
How much longer is the road route than the straight-line distance?
The direct path is about 48.5 miles (78.1 km), while the road route adds roughly 13.9 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 8:00 AM to 10:00 AM CDT. If you want a more comfortable same-day return, try to leave by 3:38 PM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $8.30 one way or $16.59 round trip. Estimated CO2 is about 19.6 kg one way.
What should you check before leaving?
Before you leave, expect Mostly Sunny around O'Fallon and Mostly Sunny near Sullivan.
Stop Ideas Near Gray Summit
Useful break, food, and waypoint ideas within about 15 miles of the route midpoint.
Transit and Meeting Points
Useful pickup, handoff, or rendezvous points close to Gray Summit.
Washington
Kirkwood
Gateway Transportation Center
Hermann
Flight Path Map
This map shows the direct air route between O'Fallon and Sullivan. Straight-line distance: 48.51 mi (78.07 km).
#1 O'Fallon
The most populous city in St.
| Population | 89,769 |
| Coordinates | 38.8106100, -90.6998500 |
| Altitude | 165 |
| Country | United States |
#2 Sullivan
City in Missouri
| Population | 7,117 |
| Coordinates | 38.2081000, -91.1604200 |
| Altitude | 299 |
| Country | United States |
End: Sullivan (-91.16042, 38.2081)
Estimated Travel Time
Distance: 100 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 02h 04m |
| 40 mph (64.37 km/h) | 01h 33m |
| 50 mph (80.47 km/h) | 01h 14m |
| 60 mph (96.56 km/h) | 01h 02m |
| 70 mph (112.65 km/h) | 00h 53m |
| 80 mph (129 km/h) | 00h 46m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $8.30 | $16.59 |
| Mid-grade | $4.25 | $9.36 | $18.71 |
| Premium | $4.65 | $10.24 | $20.48 |
| Diesel | $5.30 | $11.67 | $23.34 |
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 Missouri · May 05, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.