How far is Clayton, MO from O'Fallon, MO?
The driving distance from Clayton, MO to O'Fallon, MO is about 29.8 miles (48 km), with a travel time of about 00h 32m by car.
- The straight-line flight distance is about 23.4 miles (37.6 km).
- For a round trip, plan for roughly 01h 05m 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 32m.
This is a short drive, so your comfort window is wide. Traffic and current weather matter more than the clock.
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.
Route Weather Snapshot
Check the forecast at both ends before you head out.
Slight Chance Showers And Thunderstorms
Mostly Cloudy then Slight Chance Showers And Thunderstorms
Driving Route Map
The map below follows the saved road route between Clayton and O'Fallon.
Turn-by-Turn Driving Directions
Step-by-step road directions between Clayton and O'Fallon.
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1
Start on Hillvale Drive
54 m · 8 sec · Hillvale Drive
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2
Turn left onto Wydown Boulevard
3092 ft · 2 min · Wydown Boulevard
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3
At the end of the road, turn right onto South Hanley Road
1392 ft · 31 sec · South Hanley Road
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4
Turn left onto Shaw Park Drive
1731 ft · 33 sec · Shaw Park Drive
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5
Take the ramp straight toward Forest Park Parkway West
90 m · 6 sec
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6
Merge slight left onto Forest Park Parkway
1847 ft · 40 sec · Forest Park Parkway
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7
Keep slight right to continue on I 170 North
1070 ft · 37 sec
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8
Merge slight left onto Inner Belt Expressway
6.1 mi · 8 min · Inner Belt Expressway
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9
Take the exit slight left toward I 70 West: Kansas City
2159 ft · 37 sec
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10
Merge slight right
19.8 mi · 25 min
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11
Take the exit slight right toward MO K: O'Fallon, Main Street
119 m · 8 sec
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12
Turn straight onto East Terra Lane
1.4 km · 2 min · East Terra Lane
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13
Turn right onto South Main Street
2830 ft · 1 min · South Main Street
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14
Turn right
8 m · 2 sec
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15
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between Clayton 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.
I 70 West
Merge slight right
19.8 mi · 00h 25m
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.
Slight Chance Showers And Thunderstorms leaving Clayton and Mostly Cloudy then Slight Chance 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 Clayton to O'Fallon?
The road trip is about 29.8 miles (48 km) and usually takes 00h 32m 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?
Bridgeton is a useful midpoint, sitting about 14.8 miles from Clayton and 15 miles from O'Fallon.
How much longer is the road route than the straight-line distance?
The direct path is about 23.4 miles (37.6 km), while the road route adds roughly 6.4 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 7:24 PM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $3.96 one way or $7.92 round trip. Estimated CO2 is about 9.3 kg one way.
What should you check before leaving?
Before you leave, expect Slight Chance Showers And Thunderstorms around Clayton and Mostly Cloudy then Slight Chance Showers And Thunderstorms near O'Fallon.
Stop Ideas Near Bridgeton
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 Bridgeton.
Kirkwood
Gateway Transportation Center
Alton
Washington
Flight Path Map
This map shows the direct air route between Clayton and O'Fallon. Straight-line distance: 23.36 mi (37.6 km).
#1 Clayton
Inner-ring suburb of St.
| Population | 16,775 |
| Coordinates | 38.6425500, -90.3237300 |
| Altitude | 173 |
| 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: 48 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 00h 59m |
| 40 mph (64.37 km/h) | 00h 44m |
| 50 mph (80.47 km/h) | 00h 35m |
| 60 mph (96.56 km/h) | 00h 29m |
| 70 mph (112.65 km/h) | 00h 25m |
| 80 mph (129 km/h) | 00h 22m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $3.96 | $7.92 |
| Mid-grade | $4.25 | $4.47 | $8.93 |
| Premium | $4.65 | $4.89 | $9.77 |
| Diesel | $5.30 | $5.57 | $11.14 |
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 25, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.