How far is Saint Peters, MO from O'Fallon, MO?
The driving distance from Saint Peters, MO to O'Fallon, MO is about 4.5 miles (7.3 km), with a travel time of about 00h 06m by car.
- The straight-line flight distance is about 4 miles (6.5 km).
- For a round trip, plan for roughly 00h 12m of driving time before adding stops, traffic, or weather delays.
- A comfortable departure window is usually 7:00 AM to 7:00 PM CDT.
Reverse, save, or send this route
This is an easy same-day return drive. Copy the route link, send it to another device, or print a clean version before you head out.
This is an easy same-day return drive.
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 00h 06m.
This is a short drive, so your comfort window is wide. Traffic and current weather matter more than the clock.
This departure sits inside the recommended comfort window for the route.
Halfway Point
A useful midpoint for breaks, coffee, or meeting in the middle.
City in Saint Charles County, Missouri, United States
Route Weather Snapshot
Check the forecast at both ends before you head out.
Showers And Thunderstorms
Showers And Thunderstorms
Driving Route Map
The map below follows the saved road route between Saint Peters and O'Fallon.
Turn-by-Turn Driving Directions
Step-by-step road directions between Saint Peters and O'Fallon.
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1
Start on the route
3 mi · 4 min
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2
Take the exit slight right toward MO K: O'Fallon, Main Street
119 m · 8 sec
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3
Turn straight onto East Terra Lane
1.4 km · 2 min · East Terra Lane
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4
Turn right onto South Main Street
2830 ft · 1 min · South Main Street
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5
Turn right
8 m · 2 sec
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6
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between Saint Peters and O'Fallon.
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.
Longest stretch
Start on the route
3.02 mi · 00h 04m
Route Summary
A quick read on whether this route feels easy, ambitious, or worth planning around.
A short regional drive
This route is short enough to handle as a quick errand, commute, or easy same-day return without much planning overhead.
Showers And Thunderstorms leaving Saint Peters and Showers And Thunderstorms near O'Fallon.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Saint Peters to O'Fallon?
The road trip is about 4.5 miles (7.3 km) and usually takes 00h 06m in normal driving conditions.
Is this a same-day trip or an overnight route?
This route is short enough to handle as a quick errand, commute, or easy same-day return without much planning overhead.
What is the halfway point on this route?
Cottleville is a useful midpoint, sitting about 2.2 miles from Saint Peters and 2.3 miles from O'Fallon.
How much longer is the road route than the straight-line distance?
The direct path is about 4 miles (6.5 km), while the road route adds roughly 0.5 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 7:00 AM to 7:00 PM CDT. If you want a more comfortable same-day return, try to leave by 8:18 PM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $0.60 one way or $1.21 round trip. Estimated CO2 is about 1.4 kg one way.
What should you check before leaving?
Before you leave, expect Showers And Thunderstorms around Saint Peters and Showers And Thunderstorms near O'Fallon.
Stop Ideas Near Cottleville
Useful break, food, and waypoint ideas within about 15 miles of the route midpoint.
City Hall Park
City of O'Fallon
Swingley Ridge @ Chesterfield City Hall SB
Transit and Meeting Points
Useful pickup, handoff, or rendezvous points close to Cottleville.
Kirkwood
Washington
Gateway Transportation Center
Alton
Flight Path Map
This map shows the direct air route between Saint Peters and O'Fallon. Straight-line distance: 4.01 mi (6.46 km).
#1 Saint Peters
The most populous city in St.
| Population | 58,043 |
| Coordinates | 38.8003300, -90.6265100 |
| Altitude | 134 |
| 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: 7 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 00h 09m |
| 40 mph (64.37 km/h) | 00h 06m |
| 50 mph (80.47 km/h) | 00h 05m |
| 60 mph (96.56 km/h) | 00h 04m |
| 70 mph (112.65 km/h) | 00h 03m |
| 80 mph (129 km/h) | 00h 03m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $0.60 | $1.21 |
| Mid-grade | $4.25 | $0.68 | $1.36 |
| Premium | $4.65 | $0.74 | $1.49 |
| Diesel | $5.30 | $0.85 | $1.70 |
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 18, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.