How far is Saint Johns, MO from O'Fallon, MO?
The driving distance from Saint Johns, MO to O'Fallon, MO is about 24.1 miles (38.8 km), with a travel time of about 00h 27m by car.
- The straight-line flight distance is about 20.4 miles (32.8 km).
- For a round trip, plan for roughly 00h 55m of driving time before adding stops, traffic, or weather delays.
- A comfortable departure window is usually 7:00 AM to 7:00 PM CST.
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 27m.
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.
A city in St.
Route Weather Snapshot
Check the forecast at both ends before you head out.
Slight Chance Drizzle then Partly Sunny
Slight Chance Drizzle
Driving Route Map
The map below follows the saved road route between Saint Johns and O'Fallon.
Turn-by-Turn Driving Directions
Step-by-step road directions between Saint Johns and O'Fallon.
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1
Start on Hilleman Avenue
32 m · 10 sec · Hilleman Avenue
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2
Turn left onto Betty Lee Avenue
139 m · 22 sec · Betty Lee Avenue
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3
Turn right onto Walton Road
1740 ft · 1 min · Walton Road
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4
Turn right onto Hume Avenue
1058 ft · 50 sec · Hume Avenue
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5
Turn left onto McKibbon Road
33 m · 8 sec · McKibbon Road
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6
Turn right onto Saint Charles Rock Road
4.4 mi · 8 min · Saint Charles Rock Road
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7
Take the ramp right toward I 70 West
1394 ft · 20 sec
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8
Merge slight left
15.4 mi · 19 min
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9
Take the exit slight right toward MO K: O'Fallon, Main Street
119 m · 8 sec
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10
Turn straight onto East Terra Lane
1.4 km · 2 min · East Terra Lane
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11
Turn right onto South Main Street
2830 ft · 1 min · South Main Street
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12
Turn right
8 m · 2 sec
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13
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between Saint Johns 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 left
15.4 mi · 00h 19m
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 Drizzle then Partly Sunny leaving Saint Johns and Slight Chance Drizzle near O'Fallon.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Saint Johns to O'Fallon?
The road trip is about 24.1 miles (38.8 km) and usually takes 00h 27m 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?
Saint Charles is a useful midpoint, sitting about 11.1 miles from Saint Johns and 13 miles from O'Fallon.
How much longer is the road route than the straight-line distance?
The direct path is about 20.4 miles (32.8 km), while the road route adds roughly 3.7 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 CST. If you want a more comfortable same-day return, try to leave by 7:34 PM CST.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $3.23 one way or $6.46 round trip. Estimated CO2 is about 7.6 kg one way.
What should you check before leaving?
Before you leave, expect Slight Chance Drizzle then Partly Sunny around Saint Johns and Slight Chance Drizzle near O'Fallon.
Stop Ideas Near Saint Charles
Useful break, food, and waypoint ideas within about 15 miles of the route midpoint.
City Hall Park
Jennings City Hall
Ferguson Finance Director
Transit and Meeting Points
Useful pickup, handoff, or rendezvous points close to Saint Charles.
Kirkwood
Gateway Transportation Center
Alton
Washington
Flight Path Map
This map shows the direct air route between Saint Johns and O'Fallon. Straight-line distance: 20.36 mi (32.76 km).
#1 Saint Johns
Saint Johns is a place in Missouri, United States.
| Population | 0 |
| Coordinates | 38.7133800, -90.3431700 |
| Altitude | 185 |
| 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: 39 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 00h 48m |
| 40 mph (64.37 km/h) | 00h 36m |
| 50 mph (80.47 km/h) | 00h 28m |
| 60 mph (96.56 km/h) | 00h 24m |
| 70 mph (112.65 km/h) | 00h 20m |
| 80 mph (129 km/h) | 00h 18m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.80 | $3.23 | $6.46 |
| Mid-grade | $4.17 | $3.54 | $7.08 |
| Premium | $4.53 | $3.85 | $7.70 |
| Diesel | $6.02 | $5.11 | $10.23 |
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 · Nov 05, 2026