I-25 San Antonio Interchange Study

0.5 miles west of San Antonio between Milepost 139 to 140

NMDOT Control No. 1102060

US 380 approaching I-25



The NMDOT is conducting a study on Interstate 25 (I-25) between milepost 139 and milepost 140 at the U.S. Highway (US 380) Interchange, which is approximately ten miles south of Socorro and 0.5 miles west of San Antonio, New Mexico. I-25 is the major north/south interstate system.  Within the study area, I-25 is a rural, divided interstate with two 12-ft lanes in the northbound and southbound directions with 10-ft outside shoulders and 4-ft inside shoulders. US 380 consists of two 12-ft travel lanes with 8-ft wide shoulders as it approaches the nearby community of San Antonio to the east.  The purpose of the Study is to document existing conditions and develop improvement alternatives for the study area.

The land surrounding the San Antonio interchange is primarily undeveloped and rural with little to no development directly adjacent to the interstate.  Businesses and homes can be found half a mile to the east in the community of San Antonio. The San Antonio Fire District is located directly east of the interchange on the south side of US 380. Cattle grazing and agriculture are the primary land uses in the vicinity of the study area.  Approximately 3.3 miles to the south, the Bosque del Apache National Wildlife Refuge is located between the Chupadera Mountains and the San Pascual Mountains and encompasses more than 57,000 acres. Approximately 21.3 miles away to the north, the Sevilleta National Wildlife Refuge is a 230,000-acre wildlife refuge bisected by the Rio Grande. National wildlife refuges allow recreation users a place to camp, hike, hunt, picnic and watch wildlife. Approximately 7.8 miles to the east, the White Sands Missile Range stretches along US 380 south and encompasses more than two million acres. The WSMR occurs to the east of the Rio Grande and is managed by the US Army.

I25 San Antonio Interchange Study Area

Study Area Map (click on image to enlarge).


The study will document existing roadway geometry, drainage structures, bridge structures, and access control.  The study team will identify areas of concern, seek public and stakeholder feedback, and develop improvement alternatives.  Potential issues include:

Roadway Geometry: The roadway geometry of the entrance and exit ramps for the interchange are critical elements that will need to be evaluated for any deficiencies.

Drainage Structures: Drainage is a significant part of all highway improvement studies, and the I-25 San Antonio Interchange is no different. One significant part of this interchange Study will be the Walnut Creek improvements. Walnut Creek is a regional drainage channel that passes through the Study limits.

Bridge Structures: Five bridge structures are in the interchange area. The structures are more than 50 years old and reaching the end of their typical service life and are currently showing signs of dilapidation and disrepair.

Access Control: An access road on the western side of the interchange connects a rural roadway to the developed roadway system. The intersection between the unpaved rural roadway and the developed roadways is in the SB entrance and exit ramp areas. The potential for conflicting movements inherently created from this intersection is a safety concern for the interstate system.


Funding for the study phase currently includes state funds through House Bill 2-2021 Legislative Session (HB2-21) under Control Number 1102060.




District 1

STIP Number


Study and Design


Mark Salazar, PE
Project Development Engineer
(575) 888-7146



in the Public Meeting held on November 16, 2022

If you were unable to attend and would like to learn more, please review the public meeting summary below.

Check back regularly for updates on how you can get involved!


I-25/US 380 Interchange

View looking northwest at the I-25/US 380 Interchange. The interchange occurs at an approximate elevation of 4,660 feet and the surrounding landscape is flat with rolling hills, large geologic features in the background and some incised washes, with Walnut Creek occurring below the north end of the interchange.

Southbound I-25 Exit Ramp Crossing

The southbound I-25 exist ramp spans Walnut Creek and consists of a series of concrete box culverts that were constructed in 1939.

Walnut Creek

View of Walnut Creek looking west (upstream). Walnut Creek is an ephemeral tributary to the Rio Grande, with a convergence approximately 1.6 miles to the east. I-25 Bridge No. 6456 (carrying northbound traffic) and Bridge No. 6457 (carying southbound traffic) span Walnut Creek in the foreground.  The I-25 southbound exist ramp is seen in the background on the west side of the crossing.  

I-25 San Antonio Interchange Study – Public Involvement Plan
August 2022

I-25 San Antonio Interchange Study