How far is Farmington, MO from O'Fallon, MO?
The driving distance from Farmington, MO to O'Fallon, MO is about 94.2 miles (151.6 km), with a travel time of about 01h 32m by car.
- The straight-line flight distance is about 72.7 miles (117 km).
- For a round trip, plan for roughly 03h 05m 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 32m.
A morning start gives you useful time at the destination and keeps the return out of the late evening.
This departure sits inside the recommended comfort window for the route.
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.
Driving Route Map
The map below follows the saved road route between Farmington and O'Fallon.
Turn-by-Turn Driving Directions
Step-by-step road directions between Farmington and O'Fallon.
-
1
Start on North Jefferson Street
158 m · 25 sec · North Jefferson Street
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2
Turn right onto West Spring Street
76 m · 15 sec · West Spring Street
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3
Turn left onto North Washington Street
1895 ft · 56 sec · North Washington Street
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4
Turn left onto West Karsch Boulevard
1.1 mi · 2 min · West Karsch Boulevard
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5
Keep slight right
15 mi · 17 min
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6
Continue straight
18.9 mi · 22 min
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7
Keep slight right
1750 ft · 27 sec
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8
Take the exit straight toward I 55 North: Saint Louis
1735 ft · 49 sec
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9
Merge slight left
20.5 mi · 22 min
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10
Continue on Rosa Parks Highway
1.3 mi · 2 min · Rosa Parks Highway
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11
Take the exit slight right toward I 270 West, I 255 East: Kansas City, Chicago
1279 ft · 27 sec
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12
Keep slight left to continue on I 270 West: Kansas City
118 m · 8 sec
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13
Continue on I 270 West
1.2 km · 1 min
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14
Merge slight left
18.1 mi · 23 min
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15
Take the exit slight right toward I 70: Kansas City, Saint Louis, Saint Louis Lambert International Airport
1 mi · 1 min
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16
Keep slight left to continue on I 70 West: Kansas City
645 ft · 11 sec
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17
Continue on I 70 West: Kansas City
1 km · 57 sec
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18
Merge slight left
13.6 mi · 17 min
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19
Take the exit slight right toward MO K: O'Fallon, Main Street
119 m · 8 sec
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20
Turn straight onto East Terra Lane
1.4 km · 2 min · East Terra Lane
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21
Turn right onto South Main Street
2830 ft · 1 min · South Main Street
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22
Turn right
8 m · 2 sec
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23
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between Farmington and O'Fallon.
Highway-focused drive
Most of the mileage stays on named highways, so the important moments are ramps, exits, merges, and the final local approach.
I 55 North
Merge slight left
20.5 mi · 00h 23m
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.
Sunny leaving Farmington 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 Farmington to O'Fallon?
The road trip is about 94.2 miles (151.6 km) and usually takes 01h 32m 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?
Barnhart is a useful midpoint, sitting about 47.1 miles from Farmington and 47.1 miles from O'Fallon.
How much longer is the road route than the straight-line distance?
The direct path is about 72.7 miles (117 km), while the road route adds roughly 21.5 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 8:00 AM to 10:00 AM CDT. If you want a more comfortable same-day return, try to leave by 3:24 PM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $12.56 one way or $25.11 round trip. Estimated CO2 is about 29.6 kg one way.
What should you check before leaving?
Before you leave, expect Sunny around Farmington and Sunny near O'Fallon.
Stop Ideas Near Barnhart
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 Barnhart.
Kirkwood
Gateway Transportation Center
Washington
Alton
Flight Path Map
This map shows the direct air route between Farmington and O'Fallon. Straight-line distance: 72.73 mi (117.04 km).
#1 Farmington
City in St.
| Population | 18,674 |
| Coordinates | 37.7808800, -90.4217900 |
| Altitude | 278 |
| 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: 152 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 03h 08m |
| 40 mph (64.37 km/h) | 02h 21m |
| 50 mph (80.47 km/h) | 01h 53m |
| 60 mph (96.56 km/h) | 01h 34m |
| 70 mph (112.65 km/h) | 01h 20m |
| 80 mph (129 km/h) | 01h 10m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $12.56 | $25.11 |
| Mid-grade | $4.25 | $14.16 | $28.32 |
| Premium | $4.65 | $15.50 | $31.00 |
| Diesel | $5.30 | $17.66 | $35.32 |
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 · Jun 02, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.