How far is Flat River, MO from Saint Peters, MO?
The driving distance from Flat River, MO to Saint Peters, MO is about 84 miles (135.2 km), with a travel time of about 01h 23m by car.
- The straight-line flight distance is about 65.9 miles (106.1 km).
- For a round trip, plan for roughly 02h 46m 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 23m.
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.
Census designated place
Route Weather Snapshot
Check the forecast at both ends before you head out.
Mostly Sunny
Driving Route Map
The map below follows the saved road route between Flat River and Saint Peters.
Turn-by-Turn Driving Directions
Step-by-step road directions between Flat River and Saint Peters.
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1
Start on Crane Street
93 m · 9 sec · Crane Street
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2
Turn right onto East Main Street
723 ft · 14 sec · East Main Street
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3
Keep slight right to continue on West Main Street
697 ft · 17 sec · West Main Street
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4
Turn right onto Coffman Street
116 m · 8 sec · Coffman Street
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5
Turn slight left onto Taylor Avenue
1.4 km · 2 min · Taylor Avenue
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6
Continue on South Desloge Drive
2 mi · 3 min · South Desloge Drive
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7
Take the ramp left toward US 67 North: Saint Louis
877 ft · 22 sec
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8
Merge slight left
26.3 mi · 30 min
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9
Keep slight right
1750 ft · 27 sec
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10
Take the exit straight toward I 55 North: Saint Louis
1735 ft · 49 sec
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11
Merge slight left
20.5 mi · 22 min
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12
Continue on Rosa Parks Highway
1.3 mi · 2 min · Rosa Parks Highway
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13
Take the exit slight right toward I 270 West, I 255 East: Kansas City, Chicago
1279 ft · 27 sec
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14
Keep slight left to continue on I 270 West: Kansas City
118 m · 8 sec
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15
Continue on I 270 West
1.2 km · 1 min
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16
Merge slight left
18.1 mi · 23 min
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17
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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18
Keep slight left to continue on I 70 West: Kansas City
645 ft · 11 sec
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19
Continue on I 70 West: Kansas City
1 km · 57 sec
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20
Merge slight left
10.5 mi · 13 min
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21
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between Flat River and Saint Peters.
Highway-focused drive
Most of the mileage stays on named highways, so the important moments are ramps, exits, merges, and the final local approach.
US 67 North
Merge slight left
26.3 mi · 00h 30m
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 Flat River and Mostly Sunny near Saint Peters.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Flat River to Saint Peters?
The road trip is about 84 miles (135.2 km) and usually takes 01h 23m 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 41.9 miles from Flat River and 42.1 miles from Saint Peters.
How much longer is the road route than the straight-line distance?
The direct path is about 65.9 miles (106.1 km), while the road route adds roughly 18.1 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 8:00 AM to 10:00 AM CDT. If you want a more comfortable same-day return, try to leave by 3:44 PM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $11.16 one way or $22.32 round trip. Estimated CO2 is about 26.3 kg one way.
What should you check before leaving?
Before you leave, expect Sunny around Flat River and Mostly Sunny near Saint Peters.
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 Flat River and Saint Peters. Straight-line distance: 65.93 mi (106.1 km).
#1 Flat River
River in Michigan, United States of America
| Population | 5,157 |
| Coordinates | 37.8500500, -90.5167900 |
| Altitude | 219 |
| Country | United States |
#2 Saint Peters
The most populous city in St.
| Population | 58,043 |
| Coordinates | 38.8003300, -90.6265100 |
| Altitude | 134 |
| Country | United States |
End: I 70 West (-90.626511, 38.800311)
Estimated Travel Time
Distance: 135 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 02h 47m |
| 40 mph (64.37 km/h) | 02h 06m |
| 50 mph (80.47 km/h) | 01h 40m |
| 60 mph (96.56 km/h) | 01h 24m |
| 70 mph (112.65 km/h) | 01h 12m |
| 80 mph (129 km/h) | 01h 02m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $11.16 | $22.32 |
| Mid-grade | $4.25 | $12.59 | $25.18 |
| Premium | $4.65 | $13.78 | $27.55 |
| Diesel | $5.30 | $15.70 | $31.40 |
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.