Cameron County leaders are bullish on the new South Padre Island causeway. TxDOT wants your feedback

For the past five decades, only one bridge has connected South Padre Island to the rest of the Rio Grande Valley’s mainland, with three main roadways leading traffic to the island: Farm-to-Market Road 510, State Highway 100, and State Highway 48. 

But that may change with the construction of a second bridge, estimated to cost between $800 million and $1 billion. Construction is expected to begin by 2029, despite years of plans that have fallen through several times. 

Cameron County officials lauded the plan for its impact on emergency evacuation, its ability to ease traffic congestion, and its potential to spur economic development on the north side of the island. 

“It will allow the island to continue to grow and develop that northern part of the island,” said Pete Sepulveda, Cameron County administrator and executive director of the Cameron County Regional Mobility Authority. “I’m convinced that it is a high priority for the state of Texas.” 

Economic and environmental review

TxDOT is currently soliciting public feedback on the project as it prepares an updated environmental impact report, which is expected to receive approval in 2026. 

A 2012 federal environmental study found that capturing runoff before it enters the bay could reduce pollution, protect seagrass and tidal flats that shelter endangered species, and help preserve the ocelot habitat.

The U.S. Fish and Wildlife Service, the U.S. Army Corps of Engineers, and the Environmental Protection Agency under the Trump Administration must sign off on the project. 

Comments are open through Nov. 21. 

There’s a virtual open house on Nov. 5 and an in-person meeting on Nov. 6 at the South Padre Island Convention Center starting at 5 p.m. 

The Queen Isabella Memorial Causeway was constructed in 1974. It carries motor vehicle traffic to and from the island, and when it’s shuttered to vehicular traffic for special events, it also serves as a bridge for runners and cyclists. 

In 2001, the causeway collapsed after barges collided with the bridge, stranding both residents and visitors for months. 

Regional connectivity and future growth

The project is now moving forward because, in 2023, the Texas Transportation Commission designated the future bridge as SH 104, adding it to the state’s highway system. That means TxDOT’s budget, from both state and federal sources, would cover the cost of the bridge. 

It was previously under the purview of the Cameron County Regional Mobility Authority as a toll road. That plan was paused in 2017 when the Texas legislature moved away from new toll road projects statewide. 

“TxDOT is working on a connecting road that will eventually connect the city of Edinburg to South Padre Island,” Sepulveda said. “So that is key to the future of the Rio Grande Valley, being able to have proper transportation infrastructure in place.” 

The big goal is to bring interstate connectivity to the Valley, such as I-69, which is under construction, but it’s happening piece by piece. The future SH 104 would run east from South Padre Island to SH 77 in Cameron County and Hidalgo County’s interconnection with SH 281.

“It’s not just a second causeway to South Padre Island because it’s got components heading west towards Hidalgo County,” he said. 

Sepulveda mentioned that the goal is for Cameron County to connect to Interstate I-37 near Corpus Christi, and said TxDOT is moving forward on three segments of SH 77 near King Ranch to bring the roadway up to interstate standards. 

“I think in the next five years or so we will have a seamless Interstate corridor that we’ve been working on for decades here in the Rio Grande Valley,” he said.