How far is St. Louis, MO from Byrnes Mill, MO?
The driving distance from St. Louis, MO to Byrnes Mill, MO is about 28.6 miles (46.1 km), with a travel time of about 00h 42m by car.
- The straight-line flight distance is about 24.5 miles (39.5 km).
- For a round trip, plan for roughly 01h 24m of driving time before adding stops, traffic, or weather delays.
- A comfortable departure window is usually 7:00 AM to 7:00 PM CDT.
Reverse, save, or send this route
This is an easy same-day return drive. Copy the route link, send it to another device, or print a clean version before you head out.
This is an easy same-day return drive.
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 42m.
This is a short drive, so your comfort window is wide. Traffic and current weather matter more than the clock.
This departure sits inside the recommended comfort window for the route.
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 Cloudy then Slight Chance Rain Showers
Partly Sunny then Chance Rain Showers
Driving Route Map
The map below follows the saved road route between St. Louis and Byrnes Mill.
Turn-by-Turn Driving Directions
Step-by-step road directions between St. Louis and Byrnes Mill.
-
1
Start on Market Street
26 m · 4 sec · Market Street
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2
Turn left onto South Tucker Boulevard
1.3 mi · 4 min · South Tucker Boulevard
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3
Turn straight onto Gravois Avenue
1619 ft · 46 sec · Gravois Avenue
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4
Take the ramp left toward I 55 South: Memphis
626 ft · 15 sec
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5
Merge slight left
9.7 mi · 12 min
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6
Take the exit slight right toward US 50, US 61, US 67, I 255, I 270: Lindbergh Boulevard, Chicago, Kansas City
1267 ft · 27 sec
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7
Keep slight right to continue on I 255, I 270: Chicago, Kansas City
3228 ft · 1 min
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8
Keep slight right to continue on I 270 West: Kansas City
1 km · 57 sec
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9
Merge slight left
2.8 mi · 3 min
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10
Take the exit slight right toward MO 30: Gravois Road
1216 ft · 30 sec
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11
Turn left
11.3 mi · 15 min
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12
Take the exit slight right toward Upper Byrnes Mill Road
33 m · 3 sec
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13
Turn slight right onto Upper Byrnes Mill Road
1.4 mi · 4 min · Upper Byrnes Mill Road
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14
Arrive at your destination
0 m · 1 sec · Upper Byrnes Mill Road
Car Route Details
A richer read on the saved driving route between St. Louis and Byrnes Mill.
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
Turn left
11.3 mi · 00h 15m
Route Summary
A quick read on whether this route feels easy, ambitious, or worth planning around.
A short regional drive
This route is short enough to handle as a quick errand, commute, or easy same-day return without much planning overhead.
Mostly Cloudy then Slight Chance Rain Showers leaving St. Louis and Partly Sunny then Chance Rain Showers near Byrnes Mill.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from St. Louis to Byrnes Mill?
The road trip is about 28.6 miles (46.1 km) and usually takes 00h 42m in normal driving conditions.
Is this a same-day trip or an overnight route?
This route is short enough to handle as a quick errand, commute, or easy same-day return without much planning overhead.
What is the halfway point on this route?
Sappington is a useful midpoint, sitting about 14.3 miles from St. Louis and 14.4 miles from Byrnes Mill.
How much longer is the road route than the straight-line distance?
The direct path is about 24.5 miles (39.5 km), while the road route adds roughly 4.1 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 7:00 AM to 7:00 PM CDT. If you want a more comfortable same-day return, try to leave by 7:06 PM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $3.81 one way or $7.62 round trip. Estimated CO2 is about 9 kg one way.
What should you check before leaving?
Before you leave, expect Mostly Cloudy then Slight Chance Rain Showers around St. Louis and Partly Sunny then Chance Rain Showers near Byrnes Mill.
Stop Ideas Near Sappington
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 Sappington.
Kirkwood
Gateway Transportation Center
Alton
Washington
Flight Path Map
This map shows the direct air route between St. Louis and Byrnes Mill. Straight-line distance: 24.53 mi (39.48 km).
#1 St. Louis
The second most populous city in Missouri and the center of the St.
| Population | 315,685 |
| Coordinates | 38.6272700, -90.1978900 |
| Altitude | 142 |
| Country | United States |
#2 Byrnes Mill
City in Jefferson County, Missouri, United States
| Population | 3,015 |
| Coordinates | 38.4378300, -90.5817900 |
| Altitude | 143 |
| Country | United States |
End: Byrnes Mill (-90.58179, 38.43783)
Estimated Travel Time
Distance: 46 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 00h 57m |
| 40 mph (64.37 km/h) | 00h 42m |
| 50 mph (80.47 km/h) | 00h 34m |
| 60 mph (96.56 km/h) | 00h 28m |
| 70 mph (112.65 km/h) | 00h 24m |
| 80 mph (129 km/h) | 00h 21m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $3.81 | $7.62 |
| Mid-grade | $4.25 | $4.30 | $8.59 |
| Premium | $4.65 | $4.70 | $9.40 |
| Diesel | $5.30 | $5.36 | $10.71 |
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 12, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.