How far is O'Fallon, MO from Lamar, MO?
The driving distance from O'Fallon, MO to Lamar, MO is about 288.4 miles (464.1 km), with a travel time of about 05h 33m by car.
- The straight-line flight distance is about 214.5 miles (345.2 km).
- For a round trip, plan for roughly 11h 07m of driving time before adding stops, traffic, or weather delays.
- A comfortable departure window is usually 6:00 AM to 8:00 AM CDT.
Reverse, save, or send this route
This drive is better planned with a longer stop or an overnight stay. Copy the route link, send it to another device, or print a clean version before you head out.
This drive is better planned with a longer stop or an overnight stay.
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 05h 33m.
An early departure helps you fit a real stop into the day without turning the return into a late-night drive.
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.
Human settlement in Missouri, United States of America
Route Weather Snapshot
Check the forecast at both ends before you head out.
Slight Chance Rain Showers then Mostly Sunny
Partly Sunny
Driving Route Map
The map below follows the saved road route between O'Fallon and Lamar.
Turn-by-Turn Driving Directions
Step-by-step road directions between O'Fallon and Lamar.
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1
Start on the route
8 m · 7 sec
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2
Turn left onto South Main Street
2865 ft · 1 min · South Main Street
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3
Continue straight
3.1 mi · 6 min
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4
Continue straight
3.4 mi · 5 min
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5
Take the ramp slight right toward I 64 East, US 40 East, US 61 South
1523 ft · 22 sec
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6
Merge slight left onto Avenue of the Saints
3.7 mi · 5 min · Avenue of the Saints
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7
Take the exit slight right toward Chesterfield Airport Road
2700 ft · 58 sec
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8
Continue on Chesterfield Airport Road
110 m · 7 sec · Chesterfield Airport Road
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9
Turn right onto Olive Street Road
64 m · 5 sec
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10
Turn right onto Olive Street Road
1.5 km · 2 min · Olive Street Road
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11
Continue on North Eatherton Road
2.4 mi · 5 min · North Eatherton Road
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12
Enter the roundabout and take exit 2 toward the route
21 m · 1 sec
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13
Exit the roundabout
4.3 mi · 7 min
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14
Enter the roundabout and take exit 2 toward the route
29 m · 2 sec
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15
Exit the roundabout
2098 ft · 45 sec
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16
Enter the roundabout and take exit 2 toward MO 100 West: Gray Summit
23 m · 2 sec
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17
Exit the roundabout onto MO 100 West: Gray Summit
1202 ft · 33 sec
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18
Merge slight left
13.3 mi · 19 min
-
19
Take the exit slight right toward I 44 West, US 50 West: St. Clair
1157 ft · 14 sec
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20
Merge slight left
194.9 mi · 3 hr 31 min
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21
Take the exit slight right toward MO 96: Avilla
2896 ft · 1 min
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22
Turn straight
36 mi · 42 min
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23
Turn right onto East Java Street
1.3 km · 1 min · East Java Street
-
24
Continue on East Northwoods Street
1212 ft · 24 sec · East Northwoods Street
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25
At the end of the road, turn right onto North Garrison Avenue
3105 ft · 55 sec · North Garrison Avenue
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26
Take the ramp slight right toward I 49 North, US 71 North: Kansas City
2198 ft · 27 sec
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27
Continue on Trooper Charles P. Corbin Memorial Highway
10.5 mi · 11 min · Trooper Charles P. Corbin Memorial Highway
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28
Continue on Purple Heart Trail
9.4 mi · 10 min · Purple Heart Trail
-
29
Take the exit slight right toward US 160: Mindenmines, Lamar
802 ft · 17 sec
-
30
Turn right
1.3 mi · 2 min
-
31
Turn left onto Broadway Street
133 m · 17 sec · Broadway Street
-
32
Turn left onto 11th Street West
60 m · 8 sec · 11th Street West
-
33
Turn right
41 m · 10 sec
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34
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between O'Fallon and Lamar.
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 44 West
Merge slight left
195 mi · 03h 31m
Route Summary
A quick read on whether this route feels easy, ambitious, or worth planning around.
A longer out-and-back drive
This is still possible in one day, but it becomes a long driving day. Leaving early and planning your stop window matters more here.
Slight Chance Rain Showers then Mostly Sunny leaving O'Fallon and Partly Sunny near Lamar.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from O'Fallon to Lamar?
The road trip is about 288.4 miles (464.1 km) and usually takes 05h 33m in normal driving conditions.
Is this a same-day trip or an overnight route?
This is still possible in one day, but it becomes a long driving day. Leaving early and planning your stop window matters more here.
What is the halfway point on this route?
Stoutland is a useful midpoint, sitting about 144.1 miles from O'Fallon and 144.3 miles from Lamar.
How much longer is the road route than the straight-line distance?
The direct path is about 214.5 miles (345.2 km), while the road route adds roughly 73.9 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 6:00 AM to 8:00 AM CDT. If you want a more comfortable same-day return, try to leave by 5:52 AM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $38.39 one way or $76.78 round trip. Estimated CO2 is about 90.5 kg one way.
What should you check before leaving?
Before you leave, expect Slight Chance Rain Showers then Mostly Sunny around O'Fallon and Partly Sunny near Lamar.
Stop Ideas Near Stoutland
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 Stoutland.
Jefferson City
Sedalia
Flight Path Map
This map shows the direct air route between O'Fallon and Lamar. Straight-line distance: 214.52 mi (345.24 km).
#1 O'Fallon
The most populous city in St.
| Population | 89,769 |
| Coordinates | 38.8106100, -90.6998500 |
| Altitude | 165 |
| Country | United States |
#2 Lamar
City in Missouri
| Population | 4,233 |
| Coordinates | 37.4950500, -94.2766100 |
| Altitude | 293 |
| Country | United States |
End: Lamar (-94.27661, 37.49505)
Estimated Travel Time
Distance: 464 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 09h 36m |
| 40 mph (64.37 km/h) | 07h 12m |
| 50 mph (80.47 km/h) | 05h 46m |
| 60 mph (96.56 km/h) | 04h 48m |
| 70 mph (112.65 km/h) | 04h 07m |
| 80 mph (129 km/h) | 03h 35m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $38.39 | $76.78 |
| Mid-grade | $4.25 | $43.30 | $86.59 |
| Premium | $4.65 | $47.38 | $94.76 |
| Diesel | $5.30 | $53.99 | $107.99 |
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 · May 01, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.