How far is Byrnes Mill, MO from St. Louis, MO?
The driving distance from Byrnes Mill, MO to St. Louis, MO is about 29.6 miles (47.7 km), with a travel time of about 00h 37m by car.
- The straight-line flight distance is about 24.5 miles (39.5 km).
- For a round trip, plan for roughly 01h 14m 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 37m.
This is a short drive, so your comfort window is wide. Traffic and current weather matter more than the clock.
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.
Showers And Thunderstorms Likely
Showers And Thunderstorms Likely
Driving Route Map
The map below follows the saved road route between Byrnes Mill and St. Louis.
Turn-by-Turn Driving Directions
Step-by-step road directions between Byrnes Mill and St. Louis.
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1
Start on Upper Byrnes Mill Road
1.4 mi · 4 min · Upper Byrnes Mill Road
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2
Merge right
1695 ft · 24 sec
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3
Take the exit left toward MO 30 East
36 m · 2 sec
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4
Merge slight right
11.5 mi · 15 min
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5
Take the exit slight right toward I 270 South
1364 ft · 20 sec
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6
Merge slight left
2.8 mi · 4 min
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7
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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8
Keep slight left to continue on I 55 North, US 61, US 67: Saint Louis
557 ft · 8 sec
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9
Continue on I 55 North, US 61, US 67: Saint Louis
797 ft · 11 sec
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10
Keep slight right to continue on I 55 North: Saint Louis
1.1 km · 2 min
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11
Keep slight right to continue on I 55 North: Saint Louis
2446 ft · 52 sec
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12
Merge slight left
9.8 mi · 12 min
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13
Take the exit slight right toward MO 30 East: Gravois Avenue
1001 ft · 24 sec
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14
Turn slight right onto Gravois Avenue
1044 ft · 27 sec · Gravois Avenue
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15
Continue on South Tucker Boulevard
1.3 mi · 3 min · South Tucker Boulevard
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16
Turn right onto Market Street
26 m · 2 sec · Market Street
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17
Arrive at your destination
0 m · 1 sec · Market Street
Car Route Details
A richer read on the saved driving route between Byrnes Mill and St. Louis.
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.
MO 30 East
Merge slight right
11.5 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.
Showers And Thunderstorms Likely leaving Byrnes Mill and Showers And Thunderstorms Likely near St. Louis.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Byrnes Mill to St. Louis?
The road trip is about 29.6 miles (47.7 km) and usually takes 00h 37m 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 14.8 miles from Byrnes Mill and 14.9 miles from St. Louis.
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 5.1 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 7:16 PM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $3.96 one way or $7.92 round trip. Estimated CO2 is about 9.3 kg one way.
What should you check before leaving?
Before you leave, expect Showers And Thunderstorms Likely around Byrnes Mill and Showers And Thunderstorms Likely near St. Louis.
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 Byrnes Mill and St. Louis. Straight-line distance: 24.53 mi (39.48 km).
#1 Byrnes Mill
City in Jefferson County, Missouri, United States
| Population | 3,015 |
| Coordinates | 38.4378300, -90.5817900 |
| Altitude | 143 |
| Country | United States |
#2 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 |
End: Market Street (-90.197859, 38.627348)
Estimated Travel Time
Distance: 48 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 00h 59m |
| 40 mph (64.37 km/h) | 00h 44m |
| 50 mph (80.47 km/h) | 00h 35m |
| 60 mph (96.56 km/h) | 00h 29m |
| 70 mph (112.65 km/h) | 00h 25m |
| 80 mph (129 km/h) | 00h 22m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $3.96 | $7.92 |
| Mid-grade | $4.25 | $4.47 | $8.93 |
| Premium | $4.65 | $4.89 | $9.77 |
| Diesel | $5.30 | $5.57 | $11.14 |
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 26, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.