How far is Gray Summit, MO from O'Fallon, MO?
The driving distance from Gray Summit, MO to O'Fallon, MO is about 32.6 miles (52.4 km), with a travel time of about 00h 46m by car.
- The straight-line flight distance is about 23.1 miles (37.1 km).
- For a round trip, plan for roughly 01h 33m 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 00h 46m.
A morning start gives you useful time at the destination and keeps the return out of the late evening.
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.
City in New Jersey
Route Weather Snapshot
Check the forecast at both ends before you head out.
Partly Sunny then Chance Showers And Thunderstorms
Partly Sunny then Slight Chance Showers And Thunderstorms
Driving Route Map
The map below follows the saved road route between Gray Summit and O'Fallon.
Turn-by-Turn Driving Directions
Step-by-step road directions between Gray Summit and O'Fallon.
-
1
Start on the route
12.8 mi · 18 min
-
2
Take the exit slight right toward MO 109
1108 ft · 31 sec
-
3
Enter the roundabout and take exit 3 toward the route
68 m · 4 sec
-
4
Exit the roundabout
157 m · 11 sec
-
5
Enter the roundabout and take exit 1 toward the route
30 m · 2 sec
-
6
Exit the roundabout
2129 ft · 45 sec
-
7
Enter the roundabout and take exit 2 toward the route
29 m · 2 sec
-
8
Exit the roundabout
4.3 mi · 7 min
-
9
Enter the roundabout and take exit 2 toward South Eatherton Road
29 m · 1 sec · South Eatherton Road
-
10
Exit the roundabout onto South Eatherton Road
2.4 mi · 5 min · South Eatherton Road
-
11
Continue on Olive Street Road
1.5 km · 2 min · Olive Street Road
-
12
Take the ramp left toward Chesterfield Airport Road
1.1 km · 1 min · Chesterfield Airport Road
-
13
Merge slight left onto Avenue of the Saints
3.1 mi · 4 min · Avenue of the Saints
-
14
Take the exit slight right toward MO K: O'Fallon
100 m · 6 sec
-
15
Merge slight right onto North Outer Road
1650 ft · 31 sec · North Outer Road
-
16
Continue on North Outer Road
946 ft · 18 sec · North Outer Road
-
17
Turn right
3.3 mi · 5 min
-
18
Continue straight
1.5 mi · 3 min
-
19
Continue straight
1.6 mi · 3 min
-
20
Continue on South Main Street
3115 ft · 2 min · South Main Street
-
21
Turn right
8 m · 2 sec
-
22
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between Gray Summit 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
Start on the route
12.8 mi · 00h 18m
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.
Partly Sunny then Chance Showers And Thunderstorms leaving Gray Summit and Partly Sunny then Slight 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 Gray Summit to O'Fallon?
The road trip is about 32.6 miles (52.4 km) and usually takes 00h 46m 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?
Wildwood is a useful midpoint, sitting about 16.3 miles from Gray Summit and 16.3 miles from O'Fallon.
How much longer is the road route than the straight-line distance?
The direct path is about 23.1 miles (37.1 km), while the road route adds roughly 9.5 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 4:56 PM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $4.34 one way or $8.67 round trip. Estimated CO2 is about 10.2 kg one way.
What should you check before leaving?
Before you leave, expect Partly Sunny then Chance Showers And Thunderstorms around Gray Summit and Partly Sunny then Slight Chance Showers And Thunderstorms near O'Fallon.
Stop Ideas Near Wildwood
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 Wildwood.
Kirkwood
Washington
Gateway Transportation Center
Alton
Flight Path Map
This map shows the direct air route between Gray Summit and O'Fallon. Straight-line distance: 23.05 mi (37.09 km).
#1 Gray Summit
Census designated place
| Population | 2,701 |
| Coordinates | 38.4897800, -90.8168000 |
| Altitude | 203 |
| 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: 52 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 01h 05m |
| 40 mph (64.37 km/h) | 00h 48m |
| 50 mph (80.47 km/h) | 00h 39m |
| 60 mph (96.56 km/h) | 00h 32m |
| 70 mph (112.65 km/h) | 00h 27m |
| 80 mph (129 km/h) | 00h 24m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $4.34 | $8.67 |
| Mid-grade | $4.25 | $4.89 | $9.78 |
| Premium | $4.65 | $5.35 | $10.70 |
| Diesel | $5.30 | $6.10 | $12.20 |
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 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.