How far is Saint Peters, MO from Union, MO?
The driving distance from Saint Peters, MO to Union, MO is about 42.8 miles (68.9 km), with a travel time of about 01h 03m by car.
- The straight-line flight distance is about 31.8 miles (51.2 km).
- For a round trip, plan for roughly 02h 07m 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 03m.
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 Saint Charles County, Missouri, United States
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 Saint Peters and Union.
Turn-by-Turn Driving Directions
Step-by-step road directions between Saint Peters and Union.
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1
Start on the route
12.2 mi · 15 min
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2
Take the exit slight right toward MO Z
812 ft · 23 sec
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3
Enter the roundabout and take exit 3 toward South Church Street
74 m · 11 sec · South Church Street
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4
Exit the roundabout onto South Church Street
1 mi · 2 min · South Church Street
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5
Continue straight
1.4 mi · 2 min
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6
Continue straight
4.9 mi · 7 min
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7
Turn right
4.9 mi · 8 min
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8
At the end of the road, turn left
3.1 mi · 4 min
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9
Continue straight
3.6 mi · 6 min
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10
Continue straight
1.1 km · 2 min
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11
At the end of the road, turn left
10 mi · 15 min
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12
Turn right onto East Independence Drive
63 m · 7 sec · East Independence Drive
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13
Turn left onto North Church Street
1.1 km · 2 min · North Church Street
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14
Turn right onto East Park Avenue
900 ft · 31 sec · East Park Avenue
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15
Turn left
19 m · 5 sec
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16
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between Saint Peters and Union.
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
12.2 mi · 00h 15m
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 Saint Peters and Mostly Sunny near Union.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Saint Peters to Union?
The road trip is about 42.8 miles (68.9 km) and usually takes 01h 03m 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?
New Melle is a useful midpoint, sitting about 21.4 miles from Saint Peters and 21.4 miles from Union.
How much longer is the road route than the straight-line distance?
The direct path is about 31.8 miles (51.2 km), while the road route adds roughly 11 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 4:22 PM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $5.69 one way or $11.39 round trip. Estimated CO2 is about 13.4 kg one way.
What should you check before leaving?
Before you leave, expect Sunny around Saint Peters and Mostly Sunny near Union.
Stop Ideas Near New Melle
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 New Melle.
Washington
Kirkwood
Hermann
Gateway Transportation Center
Flight Path Map
This map shows the direct air route between Saint Peters and Union. Straight-line distance: 31.8 mi (51.17 km).
#1 Saint Peters
The most populous city in St.
| Population | 58,043 |
| Coordinates | 38.8003300, -90.6265100 |
| Altitude | 134 |
| Country | United States |
#2 Union
City in and county seat of Franklin County, Missouri, United States
| Population | 12,094 |
| Coordinates | 38.4500500, -91.0084800 |
| Altitude | 162 |
| Country | United States |
End: Union (-91.00848, 38.45005)
Estimated Travel Time
Distance: 69 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 01h 25m |
| 40 mph (64.37 km/h) | 01h 04m |
| 50 mph (80.47 km/h) | 00h 51m |
| 60 mph (96.56 km/h) | 00h 42m |
| 70 mph (112.65 km/h) | 00h 36m |
| 80 mph (129 km/h) | 00h 32m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $5.69 | $11.39 |
| Mid-grade | $4.25 | $6.42 | $12.84 |
| Premium | $4.65 | $7.03 | $14.06 |
| Diesel | $5.30 | $8.01 | $16.02 |
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 02, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.