How far is Saint Ann, MO from O'Fallon, MO?
The driving distance from Saint Ann, MO to O'Fallon, MO is about 19.8 miles (31.8 km), with a travel time of about 00h 23m by car.
- The straight-line flight distance is about 18 miles (29 km).
- For a round trip, plan for roughly 00h 46m 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 23m.
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.
A city in St.
Route Weather Snapshot
Check the forecast at both ends before you head out.
Driving Route Map
The map below follows the saved road route between Saint Ann and O'Fallon.
Turn-by-Turn Driving Directions
Step-by-step road directions between Saint Ann and O'Fallon.
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1
Start on San Jose Lane
128 m · 25 sec · San Jose Lane
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2
Turn left onto Saint Charles Rock Road
2 mi · 4 min · Saint Charles Rock Road
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3
Take the ramp right toward I 70 West
1394 ft · 20 sec
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4
Merge slight left
15.4 mi · 19 min
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5
Take the exit slight right toward MO K: O'Fallon, Main Street
119 m · 8 sec
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6
Turn straight onto East Terra Lane
1.4 km · 2 min · East Terra Lane
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7
Turn right onto South Main Street
2830 ft · 1 min · South Main Street
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8
Turn right
8 m · 2 sec
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9
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between Saint Ann 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.
Sunny leaving Saint Ann and Sunny near O'Fallon.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Saint Ann to O'Fallon?
The road trip is about 19.8 miles (31.8 km) and usually takes 00h 23m 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 9.6 miles from Saint Ann and 10.1 miles from O'Fallon.
How much longer is the road route than the straight-line distance?
The direct path is about 18 miles (29 km), while the road route adds roughly 1.8 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 7:44 PM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $2.64 one way or $5.28 round trip. Estimated CO2 is about 6.2 kg one way.
What should you check before leaving?
Before you leave, expect Sunny around Saint Ann and Sunny 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
City of O'Fallon
Vinita Park City Hall
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 Ann and O'Fallon. Straight-line distance: 18.01 mi (28.98 km).
#1 Saint Ann
City in Saint Louis County, Missouri, United States
| Population | 12,583 |
| Coordinates | 38.7272700, -90.3831700 |
| Altitude | 177 |
| 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: 32 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 00h 39m |
| 40 mph (64.37 km/h) | 00h 29m |
| 50 mph (80.47 km/h) | 00h 23m |
| 60 mph (96.56 km/h) | 00h 19m |
| 70 mph (112.65 km/h) | 00h 16m |
| 80 mph (129 km/h) | 00h 14m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $2.64 | $5.28 |
| Mid-grade | $4.25 | $2.98 | $5.95 |
| Premium | $4.65 | $3.26 | $6.52 |
| Diesel | $5.30 | $3.71 | $7.43 |
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 19, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.