How far is Eureka, MO from O'Fallon, MO?
The driving distance from Eureka, MO to O'Fallon, MO is about 26.2 miles (42.1 km), with a travel time of about 00h 42m by car.
- The straight-line flight distance is about 21.6 miles (34.8 km).
- For a round trip, plan for roughly 01h 24m 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 42m.
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.
Village in the United States
Route Weather Snapshot
Check the forecast at both ends before you head out.
Mostly Cloudy then Chance Rain Showers
Chance Showers And Thunderstorms
Driving Route Map
The map below follows the saved road route between Eureka and O'Fallon.
Turn-by-Turn Driving Directions
Step-by-step road directions between Eureka and O'Fallon.
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1
Start on South Central Avenue
1668 ft · 1 min · South Central Avenue
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2
Turn right onto East 5th Street
1352 ft · 31 sec · East 5th Street
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3
Turn left
5.9 mi · 11 min
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4
Enter the roundabout and take exit 2 toward the route
23 m · 2 sec
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5
Exit the roundabout
618 ft · 13 sec
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6
Enter the roundabout and take exit 2 toward the route
27 m · 2 sec
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7
Exit the roundabout
157 m · 11 sec
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8
Enter the roundabout and take exit 1 toward the route
30 m · 2 sec
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9
Exit the roundabout
2129 ft · 45 sec
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10
Enter the roundabout and take exit 2 toward the route
29 m · 2 sec
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11
Exit the roundabout
4.3 mi · 7 min
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12
Enter the roundabout and take exit 2 toward South Eatherton Road
29 m · 1 sec · South Eatherton Road
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13
Exit the roundabout onto South Eatherton Road
2.4 mi · 5 min · South Eatherton Road
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14
Continue on Olive Street Road
1.5 km · 2 min · Olive Street Road
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15
Take the ramp left toward Chesterfield Airport Road
1.1 km · 1 min · Chesterfield Airport Road
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16
Merge slight left onto Avenue of the Saints
3.1 mi · 4 min · Avenue of the Saints
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17
Take the exit slight right toward MO K: O'Fallon
100 m · 6 sec
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18
Merge slight right onto North Outer Road
1650 ft · 31 sec · North Outer Road
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19
Continue on North Outer Road
946 ft · 18 sec · North Outer Road
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20
Turn right
3.3 mi · 5 min
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21
Continue straight
1.5 mi · 3 min
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22
Continue straight
1.6 mi · 3 min
-
23
Continue on South Main Street
3115 ft · 2 min · South Main Street
-
24
Turn right
8 m · 2 sec
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25
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between Eureka 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
Turn left
5.92 mi · 00h 11m
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.
Mostly Cloudy then Chance Rain Showers leaving Eureka and 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 Eureka to O'Fallon?
The road trip is about 26.2 miles (42.1 km) and usually takes 00h 42m 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?
Weldon Spring Heights is a useful midpoint, sitting about 13 miles from Eureka and 13.1 miles from O'Fallon.
How much longer is the road route than the straight-line distance?
The direct path is about 21.6 miles (34.8 km), while the road route adds roughly 4.6 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 7:06 PM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $3.47 one way or $6.94 round trip. Estimated CO2 is about 8.2 kg one way.
What should you check before leaving?
Before you leave, expect Mostly Cloudy then Chance Rain Showers around Eureka and Chance Showers And Thunderstorms near O'Fallon.
Stop Ideas Near Weldon Spring Heights
Useful break, food, and waypoint ideas within about 15 miles of the route midpoint.
City Hall Park
City of O'Fallon
Transit and Meeting Points
Useful pickup, handoff, or rendezvous points close to Weldon Spring Heights.
Kirkwood
Washington
Gateway Transportation Center
Alton
Flight Path Map
This map shows the direct air route between Eureka and O'Fallon. Straight-line distance: 21.64 mi (34.82 km).
#1 Eureka
Eureka is a place in Missouri, United States.
| Population | 0 |
| Coordinates | 38.5025500, -90.6279000 |
| Altitude | 139 |
| 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: 42 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 00h 52m |
| 40 mph (64.37 km/h) | 00h 39m |
| 50 mph (80.47 km/h) | 00h 31m |
| 60 mph (96.56 km/h) | 00h 26m |
| 70 mph (112.65 km/h) | 00h 22m |
| 80 mph (129 km/h) | 00h 19m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $3.47 | $6.94 |
| Mid-grade | $4.25 | $3.91 | $7.83 |
| Premium | $4.65 | $4.28 | $8.56 |
| Diesel | $5.30 | $4.88 | $9.76 |
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 12, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.