How far is O'Fallon, MO from Dexter, MO?
The driving distance from O'Fallon, MO to Dexter, MO is about 191.1 miles (307.6 km), with a travel time of about 03h 37m by car.
- The straight-line flight distance is about 145 miles (233.3 km).
- For a round trip, plan for roughly 07h 15m 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 03h 37m.
An early departure helps you fit a real stop into the day without turning the return into a late-night drive.
This departure sits inside the recommended comfort window for the route.
Halfway Point
A useful midpoint for breaks, coffee, or meeting in the middle.
City in Missouri, United States
Route Weather Snapshot
Check the forecast at both ends before you head out.
Mostly Sunny
Mostly Sunny
Driving Route Map
The map below follows the saved road route between O'Fallon and Dexter.
Turn-by-Turn Driving Directions
Step-by-step road directions between O'Fallon and Dexter.
-
1
Start on the route
8 m · 7 sec
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2
Turn left onto South Main Street
3116 ft · 2 min · South Main Street
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3
Turn left onto Drennen Parkway
1.4 km · 1 min · Drennen Parkway
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4
Take the ramp slight left toward I 70 East: Saint Louis
133 m · 6 sec
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5
Merge slight left
13.5 mi · 17 min
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6
Take the exit slight right toward I 270: Chicago, Memphis
872 ft · 12 sec
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7
Keep slight right to continue on I 270 South: Memphis
2339 ft · 33 sec
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8
Continue on I 270 South: Memphis
723 ft · 10 sec
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9
Merge slight left
19 mi · 24 min
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10
Take the exit slight right toward I 55, US 61, US 67: Saint Louis, Memphis, Lemay Ferry Road
1911 ft · 27 sec
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11
Keep slight right to continue on I 55 South: Memphis
2031 ft · 44 sec
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12
Merge slight left onto Rosa Parks Highway
1.5 mi · 2 min · Rosa Parks Highway
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13
Continue on Officer Thomas G. Smith, Jr. Memorial Highway
1.8 mi · 2 min · Officer Thomas G. Smith, Jr. Memorial Highway
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14
Continue on Police Officer Steven Jarvis Memorial Highway
126.7 mi · 2 hr 16 min · Police Officer Steven Jarvis Memorial Highway
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15
Take the exit slight right toward US 60 West: Dexter, Poplar Bluff
2865 ft · 1 min
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16
Merge slight left
22.6 mi · 26 min
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17
Take the exit slight right toward MO 25, US 60 Business: Dexter, Bloomfield
1579 ft · 41 sec
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18
Turn left
1.4 mi · 2 min
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19
Turn right
2184 ft · 49 sec
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20
Turn left onto North Walnut Street
1341 ft · 37 sec · North Walnut Street
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21
Arrive at your destination
0 m · 1 sec · North Walnut Street
Car Route Details
A richer read on the saved driving route between O'Fallon and Dexter.
Highway-focused drive
Most of the mileage stays on named highways, so the important moments are ramps, exits, merges, and the final local approach.
Police Officer Steven Jarvis Memorial Highway
Continue on Police Officer Steven Jarvis Memorial Highway
127 mi · 02h 16m
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.
Mostly Sunny leaving O'Fallon and Mostly Sunny near Dexter.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from O'Fallon to Dexter?
The road trip is about 191.1 miles (307.6 km) and usually takes 03h 37m 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?
Saint Mary is a useful midpoint, sitting about 95.6 miles from O'Fallon and 95.6 miles from Dexter.
How much longer is the road route than the straight-line distance?
The direct path is about 145 miles (233.3 km), while the road route adds roughly 46.1 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 9:44 AM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $25.42 one way or $50.83 round trip. Estimated CO2 is about 59.9 kg one way.
What should you check before leaving?
Before you leave, expect Mostly Sunny around O'Fallon and Mostly Sunny near Dexter.
Stop Ideas Near Saint Mary
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 Saint Mary.
Du Quoin
Carbondale station
Gateway Transportation Center
Kirkwood
Flight Path Map
This map shows the direct air route between O'Fallon and Dexter. Straight-line distance: 144.98 mi (233.32 km).
#1 O'Fallon
The most populous city in St.
| Population | 89,769 |
| Coordinates | 38.8106100, -90.6998500 |
| Altitude | 165 |
| Country | United States |
#2 Dexter
City in Stoddard County, Missouri, United States
| Population | 7,839 |
| Coordinates | 36.7958900, -89.9578700 |
| Altitude | 113 |
| Country | United States |
End: Dexter (-89.95787, 36.79589)
Estimated Travel Time
Distance: 308 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 06h 22m |
| 40 mph (64.37 km/h) | 04h 46m |
| 50 mph (80.47 km/h) | 03h 49m |
| 60 mph (96.56 km/h) | 03h 11m |
| 70 mph (112.65 km/h) | 02h 43m |
| 80 mph (129 km/h) | 02h 23m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $25.42 | $50.83 |
| Mid-grade | $4.25 | $28.67 | $57.33 |
| Premium | $4.65 | $31.37 | $62.74 |
| Diesel | $5.30 | $35.75 | $71.50 |
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 23, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.