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

This page last updated February 3, 2024

I-35 South highlight map
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:

Overview Roadway
Lanes Access
Exits Speed
Special features
and notes


As a result of NAFTA and the development of the Eagle Ford Shale oilfield south of San Antonio, along with industrial and residential growth on the South Side, I‑35 South has become an increasingly important spoke in San Antonio's freeway system. This segment serves the city's southwestern quadrant 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, and residential areas mostly front the freeway through Von Ormy.

Roadway details

I-35 South lanes map
  • 8 lanes between I‑10 West and Laredo St. with a short double-decked stretch (4 lanes on the upper levels; 4 lanes on the lower level) between Guadalupe St. and S. Alamo St.
  • 9 lanes (4 southbound, 5 northbound) between Laredo St. and US 90
  • 6 lanes between US 90 and Spur 422/Poteet-Jourdanton Hwy.
  • 4 lanes between Spur 422/Poteet-Jourdanton Hwy. and Loop 1604
I-35 South lanes map
I-35 South access roads 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, and 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 South access roads map

Click here for a list of I‑35 South exits.
I-35 South speed limit map
  • 60 mph between I‑10 West and Loop 410
  • 70 mph between Loop 410 and Loop 1604
I-35 South speed limit map
I-35 South special features map
  • Two miles of concurrent (multiplexed) from I‑10 West to US 90
    • was concurrent (multiplexed) with 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 along entire route
  • Northbound left exit to Loop 353
  • VIA Metropolitan Transit Madla Transit Center just north of Zarzamora St.
I-35 South special features map
I-35 South traffic 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 Cesar Chavez Blvd and SW Military Dr., and in the evening in both directions between I‑10 West and US 90.

Traffic volume legend
I-35 South traffic map
LOCATION 2002 2012 2017 2019 2021 2022 '12-'22
S of Commerce St.         155,500 169,296 N/A
S of Laredo St. 160,000 175,000 177,327 171,936 160,584 173,066 -1.11%
S of US 90 146,000 146,000 155,113 158,210 159,854 161,072 +10.32%
N of SW Military Dr. 104,000 107,000 115,550 116,128 106,517 116,950 +9.30%
N of Zarzamora St. 70,000 79,000 86,663 90,788 86,323 91,308 +15.58%
N of Cassin Rd. 37,000 43,000 49,228 50,360 48,915 51,499 +19.77%
N of New Laredo Hwy. 34,000 39,000 46,774 48,590 46,776 49,352 +26.54%
S of Fischer Rd. 38,000 45,000 57,722 59,644 82,263 83,046 +84.55%
N of Loop 1604         58,644 60,225 N/A

(NOTE: In 2021, TxDOT changed the location of several traffic counting stations. New stations will show no history prior to 2021, and discontinued stations will show no history for 2021 and thereafter.)


Media gallery

Click here for historical photos of this freeway.

Click here for video of this freeway.

Construction projects

There are currently no major construction projects in this corridor.

Click here to view information for all projects in this corridor.

Future plans

The Alamo Area Metropolitan Planning Organization's 25-year plan lists 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 plan. 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 finally landing on 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., through today's Port San Antonio and Kelly Field, and onto 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.

I-35 South history map
I-35 South history map
I-35 ribbon cutting at SW Military Dr. looking north in 1960

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

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

I-35 at Nogalitos St. looking south ca. 1952

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. This area is now the I‑35/I‑10/US 90 interchange.
(Photo courtesy of TxDOT)

More historical photos of I-35 are available here.