San Antonio to Monterrey distance
San Antonio and Monterrey are 281 miles (452 km) apart in a straight line and 294 miles (473 km) apart by road: about 5 hr 25 min of driving without stops, mostly on I-35 and the MEX 85. Below you’ll find the route map, both halfway points, the bearing, the time difference and where every figure comes from.
By the All Map Tools Team
- By road
- 294 mi (473 km)
- Driving time
- 5 hr 25 min
- Straight line
- 281 mi (452 km)
- Driving route
- Straight line
- Straight-line midpoint
- Halfway by road
Lambert azimuthal equal-area projection centered on the midpoint. Route: FOSSGIS OSRM with data © OpenStreetMap contributors, calculated on November 1, 2026; simplified line.
The figures
| Figure | Value |
|---|---|
| Straight line | 281 mi (452 km) geodesic on the WGS84 ellipsoid |
| By road | 294 mi (473 km) fastest driving route (OSRM) |
| Driving time | 5 hr 25 min no stops, no traffic |
| Road detour | +5% 1.05 times the straight line |
| Average speed | 54 mph (87 km/h) along the route, without stops |
| Bearing | 204° (southwest) leaving San Antonio toward Monterrey |
| Midpoint | 27.5575° N, 99.4209° W near Los Altos (Texas) |
| Halfway by road | Near Los Corralitos (Texas) 147 mi from each city by road |
| Time difference | None in winter · 1 hour behind in summer Monterrey compared with San Antonio |
| Population | San Antonio: 1,548,422 · Monterrey: 1,135,512 Census Bureau estimate for 2025; GeoNames |
San Antonio to Monterrey by road
The fastest driving route is 294 miles (473 km) long and takes about 5 hr 25 min without stops or traffic. It runs mostly on I-35 (144 mi) and the MEX 85 (126 mi).
Of the 294 mi, 157 mi are in the United States and 137 mi are in Mexico. That’s an average of 54 mph (87 km/h). AAA recommends a break every two hours or 100 miles: with 2 stops of 20 minutes, the trip takes about 6 hr 5 min. The time is OSRM’s estimate with OpenStreetMap data: no traffic and speeds somewhat below the limits, so real trips can differ.
Straight-line distance and bearing
In a straight line, the shortest distance over the Earth’s surface, San Antonio and Monterrey are 281 miles (452 km) apart. That’s the geodesic on the WGS84 ellipsoid, the distance “as the crow flies”.
The road is 5% longer: for every 100 miles in a straight line you drive 105. The route runs almost straight. Of the 16 US–Canada and US–Mexico driving pairs in this series, it has the smallest detour (the average is 22%).
From San Antonio, Monterrey lies to the southwest (bearing 204°), and from Monterrey, San Antonio lies to the northeast.
Halfway between San Antonio and Monterrey
Halfway along the straight line, 140 miles (226 km) from each city, is the point 27.5575° N, 99.4209° W. It falls near Los Altos (Texas, pop. 1,082), 5.1 mi away. The nearest town of 20,000 people or more is Nuevo Laredo (Tamaulipas, Mexico, pop. 416,055), 8.1 mi away.
By road, the halfway point is 147 miles (236 km) from each city, near Los Corralitos (Texas), 4.3 mi away. The nearest town of 20,000 people or more is Nuevo Laredo (Tamaulipas, Mexico, pop. 416,055), 11.2 mi away. The two midpoints are 6.9 mi apart: if you want to meet halfway, the one on the road is the useful one.
Time difference and flight
In winter, Monterrey is on the same time as San Antonio; in summer, 1 hour behind San Antonio. It changes because they don’t switch to summer time together.
No flight time is given: under 500 km (311 miles) in a straight line, time at the airport outweighs time in the air.
The two cities
San Antonio has 1.5 million people (Census Bureau estimate for 2025) and Monterrey 1.1 million people (GeoNames).
Frequently asked questions
How many miles is it from San Antonio to Monterrey?
281 miles (452 km) in a straight line and 294 miles (473 km) by road on the fastest route (mostly on I-35 and the MEX 85).
How long is the drive from San Antonio to Monterrey?
About 5 hr 25 min without stops or traffic, according to OSRM with OpenStreetMap data; with 2 stops of 20 minutes, about 6 hr 5 min.
Where is the halfway point between San Antonio and Monterrey?
In a straight line, near Los Altos (Texas). By road, 147 mi from each city, near Los Corralitos (Texas).
What’s the time difference between San Antonio and Monterrey?
It depends on the season: none in winter and 1 hour behind in summer (Monterrey compared with San Antonio).
Which direction is Monterrey from San Antonio?
Southwest: the straight line leaves San Antonio on a bearing of 204° (0° is north and 90° is east).
Measure it yourself on the map
The same two cities, already set up in the tools: move the points, get the route by bike or on foot and download the map.
- Distance between two points Measure the distance between any two places or points on the map, in miles or kilometers.
- Straight line vs driving distance Compare the as-the-crow-flies distance with the real driving distance and see how much the road adds.
- Halfway point Find the exact halfway point between two places and see it on the map, ready to share.
- Time difference calculator Compare the time in two or more places and find a good hour to call or meet across time zones.
Similar pairs
The ones in this series whose cities are closest to these two, in case another one suits you better.
More distances from San Antonio
All distances- Dallas to San Antonio 252 mi straight line · 273 mi by road · 4 hr 55 min
- Houston to San Antonio 190 mi straight line · 195 mi by road · 3 hr 30 min
- Austin to San Antonio 73.5 mi straight line · 79.2 mi by road · 1 hr 30 min
- San Antonio to Corpus Christi 130 mi straight line · 143 mi by road · 2 hr 30 min
Sources
- Driving route: FOSSGIS OSRM, car profile (calculated on November 1, 2026) · FOSSGIS e.V.
- Roads, streets and places · © OpenStreetMap contributors (ODbL)
- Straight line, bearings and midpoint (geodesics on the WGS84 ellipsoid) · GeographicLib (C. F. F. Karney)
- US city centers (GNIS) and their elevation (3DEP) · USGS (public domain)
- Location and population of cities outside Spain and the US · GeoNames (CC BY 4.0)
- Population estimates, Vintage 2025 · US Census Bureau (public domain)
- Places near the midpoints: All Map Tools gazetteer (GeoNames, INE, IGN and Census) · All Map Tools
- Time zones (timezone-boundary-builder outlines and the IANA database) · © OpenStreetMap contributors (ODbL)
- Map: provinces (IGN), states (US Census Bureau) and countries (Natural Earth) · IGN, Census and Natural Earth
- Methodology