How far is Houston, TX from San Marcos, TX?
The driving distance from Houston, TX to San Marcos, TX is about 165.2 miles (265.8 km), with a travel time of about 03h 03m by car.
- The straight-line flight distance is about 154.8 miles (249.1 km).
- For a round trip, plan for roughly 06h 06m of driving time before adding stops, traffic, or weather delays.
- A comfortable departure window is usually 6:00 AM to 8:00 AM CDT.
Reverse, save, or send this route
This drive is better planned with a longer stop or an overnight stay. Copy the route link, send it to another device, or print a clean version before you head out.
This drive is better planned with a longer stop or an overnight stay.
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 03h 03m.
An early departure helps you fit a real stop into the day without turning the return into a late-night drive.
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 Texas, United States
Route Weather Snapshot
Check the forecast at both ends before you head out.
Partly Sunny
Partly Sunny
Driving Route Map
The map below follows the saved road route between Houston and San Marcos.
Turn-by-Turn Driving Directions
Step-by-step road directions between Houston and San Marcos.
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1
Start on Louisiana Street
761 ft · 25 sec · Louisiana Street
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2
Take the ramp straight toward I 10 West: San Antonio
2149 ft · 52 sec
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3
Merge slight right onto Katy Freeway
136.2 mi · 2 hr 23 min · Katy Freeway
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4
Take the exit slight right toward US 90, US 183: Luling, Lockhart
1788 ft · 46 sec
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5
Merge slight left onto East Pierce Street
3.9 mi · 6 min · East Pierce Street
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6
Turn right onto South Laurel Avenue
1019 ft · 30 sec · South Laurel Avenue
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7
Turn left onto East Austin Street
1921 ft · 47 sec · East Austin Street
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8
Turn straight onto San Marcos Highway
22.2 mi · 28 min · San Marcos Highway
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9
Continue on East Hopkins Street
1.2 mi · 2 min · East Hopkins Street
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10
Turn right onto North LBJ Drive
64 m · 9 sec · North LBJ Drive
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11
Turn left
128 m · 36 sec
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12
At the end of the road, turn left onto North Guadalupe Street
43 m · 3 sec · North Guadalupe Street
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13
Arrive at your destination
0 m · 1 sec · North Guadalupe Street
Car Route Details
A richer read on the saved driving route between Houston and San Marcos.
Highway-focused drive
Most of the mileage stays on named highways, so the important moments are ramps, exits, merges, and the final local approach.
Katy Freeway
Merge slight right onto Katy Freeway
136 mi · 02h 23m
Route Summary
A quick read on whether this route feels easy, ambitious, or worth planning around.
A longer out-and-back drive
This is still possible in one day, but it becomes a long driving day. Leaving early and planning your stop window matters more here.
Partly Sunny leaving Houston and Partly Sunny near San Marcos.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Houston to San Marcos?
The road trip is about 165.2 miles (265.8 km) and usually takes 03h 03m in normal driving conditions.
Is this a same-day trip or an overnight route?
This is still possible in one day, but it becomes a long driving day. Leaving early and planning your stop window matters more here.
What is the halfway point on this route?
Weimar is a useful midpoint, sitting about 82.5 miles from Houston and 82.7 miles from San Marcos.
How much longer is the road route than the straight-line distance?
The direct path is about 154.8 miles (249.1 km), while the road route adds roughly 10.4 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 6:00 AM to 8:00 AM CDT. If you want a more comfortable same-day return, try to leave by 10:54 AM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $22.03 one way or $44.06 round trip. Estimated CO2 is about 51.8 kg one way.
What should you check before leaving?
Before you leave, expect Partly Sunny around Houston and Partly Sunny near San Marcos.
Stop Ideas Near Weimar
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 Weimar.
Prairie View, TX
Austin
San Marcos Station
Taylor
Flight Path Map
This map shows the direct air route between Houston and San Marcos. Straight-line distance: 154.76 mi (249.06 km).
#1 Houston
The fourth most populous city in the United States and the center of the Houston metropolitan area.
| Population | 2,316,120 |
| Coordinates | 29.7632800, -95.3632700 |
| Altitude | 12 |
| Country | United States |
#2 San Marcos
The most populous city in Hays County, Texas.
| Population | 66,350 |
| Coordinates | 29.8832700, -97.9413900 |
| Altitude | 188 |
| Country | United States |
End: San Marcos (-97.94139, 29.88327)
Estimated Travel Time
Distance: 266 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 05h 30m |
| 40 mph (64.37 km/h) | 04h 07m |
| 50 mph (80.47 km/h) | 03h 18m |
| 60 mph (96.56 km/h) | 02h 45m |
| 70 mph (112.65 km/h) | 02h 21m |
| 80 mph (129 km/h) | 02h 03m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.78 | $22.03 | $44.06 |
| Mid-grade | $4.25 | $24.79 | $49.58 |
| Premium | $4.59 | $26.77 | $53.53 |
| Diesel | $3.99 | $23.28 | $46.56 |
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 Texas · Apr 18, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.