Interstate 37 links San Antonio with Corpus Christi and the Gulf Coast in South Texas. IH 37 provides connectivity to the Rio Grande Valley with U.S. 281 / IH 69C and U.S. 77 / IH 69E. The freeway is also one of the only limited-access hurricane evacuation routes from the South Texas coastline inland towards San Antonio and Austin. Like IH 45, IH 37 located entirely within the Lone Star State.
Parallel U.S. Routes
IH 37 combines with U.S. 281 south from the McAllister Freeway and IH 35 at Downtown San Antonio to IH 410 at the Stinson Airport Vicinity in southeast San Antonio. U.S. 281 shifts westward along IH 410 to parallel IH 37 south to Leming and Pleasanton. The two come together again between Exits 103 and 72 near Three Rivers. U.S. 281 branches south from there toward Alice while the remainder of IH 37 mirrors the course of U.S. 181 southeast to Corpus Christi. U.S. 77 also briefly combines with IH 37 to IH 69E at Calallen in Corpus Christi.
North End – San Antonio, TX
South End – Corpus Christi, TX
Branches – 0
Mileage – 143.00
Cities – Corpus Christi, Mathis
- Junctions –
Source: December 31, 2018 Interstate Route Log and Finders List
IH 37 was completed from San Antonio south to FM 1303 (where Loop 1604 crosses IH 37 now) by 1972 and from Corpus Christi north to FM 534 at Swinney Switch.
The U.S. 181 Harbor Bridge Replacement Project, an $899 million span constructed to replace the 1959-built bridge for U.S. 181 to the east, broke ground on August 8, 2016.1,2 Four Proposed Build Alternatives were considered as of July 2013. The Red Alternative was ultimately chosen. It ties in the new 538 foot tall cable-stayed bridge2 and alignment with the interchange joining IH 37 with the Crosstown Expressway (SH 286). The exchange will be rebuilt into a new directional T interchange with high speed flyovers between north-south U.S. 181 / SH 286 and IH 37 to the west. Connections with the IH 37 spur to the east will use the frontage roads in place of direct ramps.
An additional refinement considered for the bridge design was the elimination of the Staples Street overpass above Interstate 37 to the east of the Crosstown Expressway. An at-grade intersection between the two was proposed in place of the crossing. This effort was meant to make the Downtown area more pedestrian friendly.1 It would have also shortened IH 37 by at least 0.6 miles. Work on the Harbor Bridge Replacement Project runs through April 2021.2
IH 37 was added to the original Interstate system in October 1957. It was included within the Texas Interstate Highway System by the State Highway Commission in 1962 with 142 miles.3
The proposed section of IH 37 north of Downtown San Antonio to IH 410 was the North Expressway, a route connecting Downtown with the airport. Original plans called for the freeway to travel a straight line north from Downtown. However, local opposition arose due to the potential local impacts of the freeway. A lawsuit by the San Antonio Conservation Society resulted in an injunction preventing construction of the freeway as an Interstate in 1967.
Opposition to the freeway project remained through the late 1960s and early 1970s. The struggle reached a national audience when the freeway was profiled in Helen Leavitt’s book Superhighway-Superhoax. With its proximity to or passage through parkland, a college campus, schools, residential neighborhoods and other sensitive areas, the route was changed to avoid these features. This resulted into the number of S-curves along the freeway between IH 35 and IH 410. In 1973, the freeway was resurrected as a project to be built without federal funds as a new alignment for U.S. 281. Construction ensued through the mid-1970s, and the Walter McAllister Expressway (U.S. 281) opened to traffic on February 7, 1978.4 The systems interchange providing direct connection ramps between U.S. 281 and IH 410 did not begin construction until 2006. It was completed in June 2008.
North End – San Antonio, Texas
North End Throwback
South End – Corpus Christi, Texas
Heading east from the Crosstown Expressway (SH 286) south, back to back ramps depart from IH 37 south for Buffalo Street (Exit 1A) and U.S. 181 & SH 35 north to the Harbor Bridge. The new alignment for U.S. 181 will tie into a rebuilt cloverstack interchange with SH 286 here as part of the U.S. 181 Harbor Bridge Replacement Project. Photo taken 08/03/19.
The initial stretch of IH 37 north travels below grade between Downtown Corpus Christi and Martin Luther King Drive. Ramps join the freeway from U.S. 181 south and Padre Street as the freeway progresses west a quarter mile to SH 286 (Crosstown Expressway) south. The forthcoming exchange with SH 286 will be redesigned to accommodate the new Harbor Bridge approach. Photo taken 08/03/19.
South End Throwback
SH 286 ends at the ramp split for IH 37 north to San Antonio and south to U.S. 181 (Harbor Bridge) and Shoreline Boulevard. With the new Harbor Bridge approach tying into this exchange from the north, all ramps here will be replaced as part of an interchange redesign. Photo taken by Jeff Royston (12/00).
Former button copy sign posted ahead of the U.S. 181 & SH 35 northbound off-ramp from IH 37 south. The Harbor Bridge carries both routes across Corpus Christi Channel to North Beach, where the Texas State Aquarium and the U.S.S. Lexington are located. SH 35 branches northeast from U.S. 181 in ten miles en route to Aransas Pass and Rockport. Photo taken by Jeff Royston (12/00).
Trailblazers for IH 37, U.S. 181 and SH 35 north were formerly posted at the intersection of Shoreline Boulevard north with the Interstate Highway 37 boulevard extending west to the freeway. The IH 37 end point is a rare example where an Interstate, U.S., and State Highway all conclude at the same location. Photo taken by Jeff Royston (12/01).
- “Harbor Bridge open house to show possible bridge modifications.” Corpus Christi Caller Times, June 23, 2016.
- “Groundbreaking ceremony held for Corpus Christi Harbor Bridge.” Rio Grande Guardian (TX), August 9, 2016.
- From Anywhere to Everywhere: The Development of the Interstate Highway System in Texas by Penny Beaumont, Rhonda Brinkmann, David Ellis, Chris Pourteau, and Brandon V. Webb, Texas Transportation Institute, page 29.
- From Anywhere to Everywhere: The Development of the Interstate Highway System in Texas by Penny Beaumont, Rhonda Brinkmann, David Ellis, Chris Pourteau, and Brandon V. Webb, Texas Transportation Institute, page 24.
Page updated August 12, 2019.