How far is Potosi, MO from O'Fallon, MO?
The driving distance from Potosi, MO to O'Fallon, MO is about 88.5 miles (142.5 km), with a travel time of about 01h 38m by car.
- The straight-line flight distance is about 60.6 miles (97.5 km).
- For a round trip, plan for roughly 03h 16m 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 38m.
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.
Chance Rain Showers then Slight Chance Showers And Thunderstorms
Showers And Thunderstorms Likely
Driving Route Map
The map below follows the saved road route between Potosi and O'Fallon.
Turn-by-Turn Driving Directions
Step-by-step road directions between Potosi and O'Fallon.
-
1
Start on West High Street
1 mi · 2 min · West High Street
-
2
Turn left
25.5 mi · 41 min
-
3
Continue straight
3.8 mi · 5 min
-
4
Turn left
1894 ft · 36 sec
-
5
Continue on MO 21 North: Saint Louis
19.7 mi · 23 min
-
6
Take the exit slight right toward MO 141: Arnold, Fenton
1384 ft · 24 sec
-
7
Turn left
4 mi · 6 min
-
8
Take the exit right toward MO 30 East: Saint Louis
1229 ft · 17 sec
-
9
Merge slight left
2.5 mi · 4 min
-
10
Take the exit left toward I 270 North
2202 ft · 35 sec
-
11
Merge slight left
14.7 mi · 18 min
-
12
Take the exit slight right toward I 70: Kansas City, Saint Louis, Saint Louis Lambert International Airport
1 mi · 1 min
-
13
Keep slight left to continue on I 70 West: Kansas City
645 ft · 11 sec
-
14
Continue on I 70 West: Kansas City
1 km · 57 sec
-
15
Merge slight left
13.6 mi · 17 min
-
16
Take the exit slight right toward MO K: O'Fallon, Main Street
119 m · 8 sec
-
17
Turn straight onto East Terra Lane
1.4 km · 2 min · East Terra Lane
-
18
Turn right onto South Main Street
2830 ft · 1 min · South Main Street
-
19
Turn right
8 m · 2 sec
-
20
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between Potosi and O'Fallon.
Interchange-aware route
The drive includes several ramps, exits, or merges, so checking the next few maneuvers before busy interchanges is useful.
Longest stretch
Turn left
25.5 mi · 00h 41m
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.
Chance Rain Showers then Slight Chance Showers And Thunderstorms leaving Potosi and Showers And Thunderstorms Likely near O'Fallon.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Potosi to O'Fallon?
The road trip is about 88.5 miles (142.5 km) and usually takes 01h 38m 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?
High Ridge is a useful midpoint, sitting about 44.7 miles from Potosi and 43.9 miles from O'Fallon.
How much longer is the road route than the straight-line distance?
The direct path is about 60.6 miles (97.5 km), while the road route adds roughly 27.9 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 3:14 PM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $11.80 one way or $23.61 round trip. Estimated CO2 is about 27.8 kg one way.
What should you check before leaving?
Before you leave, expect Chance Rain Showers then Slight Chance Showers And Thunderstorms around Potosi and Showers And Thunderstorms Likely near O'Fallon.
Stop Ideas Near High Ridge
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 High Ridge.
Kirkwood
Gateway Transportation Center
Washington
Alton
Flight Path Map
This map shows the direct air route between Potosi and O'Fallon. Straight-line distance: 60.59 mi (97.51 km).
#1 Potosi
County seat of Washington County, Missouri, United States
| Population | 2,548 |
| Coordinates | 37.9364400, -90.7879100 |
| Altitude | 275 |
| Country | United States |
#2 O'Fallon
The most populous city in St.
| Population | 89,769 |
| Coordinates | 38.8106100, -90.6998500 |
| Altitude | 165 |
| Country | United States |
End: (-90.699849, 38.810674)
Estimated Travel Time
Distance: 143 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 02h 57m |
| 40 mph (64.37 km/h) | 02h 12m |
| 50 mph (80.47 km/h) | 01h 46m |
| 60 mph (96.56 km/h) | 01h 28m |
| 70 mph (112.65 km/h) | 01h 15m |
| 80 mph (129 km/h) | 01h 06m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $11.80 | $23.61 |
| Mid-grade | $4.25 | $13.31 | $26.62 |
| Premium | $4.65 | $14.57 | $29.13 |
| Diesel | $5.30 | $16.60 | $33.20 |
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 · Apr 15, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.