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I-35 San Antonio Area Freeway System
Interstate 35 South (South PanAm Freeway)

This page last updated November 14, 2020

I-35 South highlight map This page covers Interstate 35 west and south of downtown San Antonio from the I-10 West interchange to Loop 1604. For information on I-35 north of downtown, see the I-35 North page.

Length: 16 miles


On this page

Lanes Access
Special features
& notes
Traffic Media


As a result of NAFTA and the development of the Eagle Ford Shale oilfield south of San Antonio, I-35 South has become an increasingly important spoke in San Antonio's freeway system. This segment serves the city's southwest side and continues on to Laredo, the busiest US-Mexico border crossing for trucks. This corridor is also an important component in the continuing development of Port San Antonio.

This segment serves downtown San Antonio, Market Square, the University of Texas at San Antonio downtown campus, the San Antonio Produce Market, South Park Mall, Palo Alto College, Texas A&M University at San Antonio, the Toyota plant and adjacent suppliers, and a growing logistics and industrial area at Loop 410 as well as the cities of Von Ormy and Somerset. Commercial and industrial development fronts the freeway near downtown. Residential and some commercial development lines the corridor south of US 90 to Somerset Rd. Mostly undeveloped land takes over south of Somerset Rd. to Loop 410. South of Loop 410, light industrial areas and two rail yards sit on the west side of the freeway between Loop 410 and Von Ormy.

Roadway details


Click here for a schematic of I-35 South.
  • 8 lanes from I-10 West to Laredo St. with a short double-decked stretch (4 lanes on the upper levels; 4 lanes on the lower level) from Guadalupe St. to S. Alamo St.
  • 9 lanes (4 southbound, 5 northbound) from Laredo St. to US 90
  • 6 lanes from US 90 to Spur 422/Poteet-Jourdanton Hwy.
  • 4 lanes from Spur 422/Poteet-Jourdanton Hwy. to Loop 1604

I-35 lanes map

  • No traditional access roads along most of the route from I-10 West to US 90, although S. Pecos-La Trinidad St. functions a southbound access road from I-10 West to S Alamo St. Short sections of access road exist on both sides between S Alamo St. and Cevallos St. A short access road exists southbound from San Marcos St. to Nogalitos St.
  • Continuous access roads along most of remainder of route
  • Access roads do not continue through Loop 410 interchange or over the Medina River, and the southbound access road does not continue through the New Laredo Hwy. interchange

I-35 access roads map


Click here for a list of I-35 South exits.

  • 60 mph from I-10 West to Loop 410
  • 70 mph from Loop 410 to Loop 1604

I-35 speed limit map

  • Two miles of I-10/US 87 concurrent (multiplexed) from I-10 West to US 90
    • US 81 was concurrent (multiplexed) over I-35 in Bexar County before it was decommissioned south of Ft. Worth in 1991
  • Double-decked freeway from just north of S. Alamo to just south of S. Laredo St.
  • TransGuide coverage from I-10 West to Southcross Blvd.
  • VIA Metropolitan Transit Madla Transit Center just north of Zarzamora St.
  • Northbound left exit to Loop 353

I-35 special features map


Generally heavy from I-10 West to SW Military Dr. Moderate to light volumes south from there. Regular peak-period congestion can be found northbound in the morning between Division Ave. and Cesar Chavez Blvd. and in the evening in both directions between I-10 West and US 90.

Traffic counts on the southern half of the corridor have increased substantially over the past decade.

Traffic volume legend

I-35 traffic map

LOCATION 1999 2009 2014 2017 2018 2019 '09-'19
S of Laredo St.169,000168,000150,358177,327179,100171,936+2.34%
S of US 90148,000141,000127,987155,113157,581158,210+12.21%
N of SW Military Dr.101,000104,000105,191115,550116,409116,128+11.66%
N of Zarzamora St.65,00074,00076,80286,66387,09290,788+22.69%
N of Somerset Rd.29,00040,00044,79349,22850,36050,360+25.90%
N of New Laredo Hwy.26,00034,00039,00046,77445,92748,590+42.91%
S of Fischer Rd.32,00041,00047,41957,72263,40559,644+45.47%

Media gallery

Click here for photos and video of this freeway.

Construction projects

No current projects in this corridor.

Future plans

The MPO's 25-year plan has proposals for the expansion of I-35 to eight lanes from US 90 to the Atascosa County line.

A new expressway (Kelly Parkway) roughly paralleling this section of I-35 is proposed as part of the Port San Antonio long-range road improvements package. It would run north from SH 16 near the Toyota plant to US 90 via General Hudnell Dr., crossing I-35 between Spur 422 and Loop 410.

A fully-directional "stack" interchange at Loop 410 is included in future plans to upgrade SW Loop 410.


The first sections to be built were simply called "US 81 Expressway", then the "South Expressway" and "Southwest Expressway" before being named the "PanAm Freeway" as it is a segment of the Pan American Highway. This freeway is also part of the so-called "NAFTA Superhighway". The designation as I-35 was authorized on October 1, 1959. US 81 was decommissioned south of Fort Worth in 1991. 

The section south of New Laredo Hwy. was built in 1934 as part of the Arneson Plan to improve state highways in Bexar County. Prior to then, US 81 and its predecessor SH 2 ran along Frio City Rd. and Pearsall Rd.

This was the first expressway spoke in Bexar County to be completed from downtown to the county line, although the section from Loop 410 to the county line was not upgraded to full Interstate standards until 1974.

  • Late 1930s: The section from Nogalitos St. to downtown was included as part of the original three-legged expressway plan for San Antonio designed to provide bypass routes around downtown for through traffic on the various US highways. The United States' entrance into World War II delayed these plans until after the war.
  • 1952: The section from Guadalupe St. to Pruitt St. (just south of Nogalitos St.) was completed as one of the three spokes of the seminal expressway system.
  • 1955: Alignment finalized for the routing of the section between Nogalitos St. and Loop 410. An earlier proposal would have used the current routing from Nogalitos St. to SW Military Dr., then would have followed SW Military Dr. to New Laredo Hwy.
  • 1956: Access roads between SW Military Dr. and New Laredo Hwy. opened and the pre-existing section of US 81 from New Laredo Hwy. to the Atascosa county line was upgraded to a "semi-expressway" (divided highway with access roads but no overpasses at intersections.)
  • 1957: The elevated "Central Expressway" segment from Guadalupe St. to present-day I-10 West was completed including "Downtown Y" interchange.
  • 1958: Access roads between Nogalitos St. and SW Military Dr. opened.
  • 1960: Freeway between Nogalitos St. and Fischer Rd. completed including the Loop 410 interchange.
  • 1967: Interchange at US 90 completed.
  • 1974: Work to upgrade the segment from Fischer Rd. to the Atascosa county line to Interstate standards was completed.
  • 1989: The section from SW Military to Spur 422 expanded from four to six lanes.
  • 1988-1991: Section from US 90 to I-10 West expanded as part of the "Downtown Y" project.
  • 1995: TransGuide coverage added from I-10 West to Southcross Blvd. as part of the original TransGuide project.
  • 2009: The section from US 90 to Somerset Rd. was reconstructed. The reconstruction removed several pedestrian bridges, expanded the overpasses and frontage roads, relocated several entrance and exit ramps, removed the previous southbound left-hand exit to SP 422 and the northbound left-hand exit to Palo Alto Rd., and extended the northbound frontage road through the Spur 422 interchange.

I-35 ribbon cutting at SW Military Dr. looking north in 1960
(Photo courtesy of TxDOT)

I-35 over San Marcos St. looking north ca. 1955
(Photo courtesy of TxDOT)

I-35 at Nogalitos St. looking south ca. 1952
The expressway ended here at this time. Southbound traffic exited onto Nogalitos St., but northbound traffic entered the ramp shown here from Pruitt Ave.
(Photo courtesy of TxDOT)

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This page and all its contents are Copyright 2019 by Brian Purcell

The information provided on this website is provided on an "as-is" basis without warranties of any kind either express or implied.  The author and his agents make no warranties or representations of any kind concerning any information contained in this website.  This website is provided only as general information.  The author expressly disclaims all liability with respect to actions taken or not taken based upon the information contained herein or with respect to any errors or omissions in such information.  All opinions expressed are strictly those of the author.  This site is not affiliated in any way with any official agency.