Matamoros–Brownsville Metropolitan Area in the context of Lower Rio Grande Valley

Matamoros, officially known as Heroica Matamoros, is a city in the northeastern Mexican state of Tamaulipas, and the municipal seat of the homonymous municipality. It is on the southern bank of the Rio Grande, directly across the border from Brownsville, Texas, United States.Matamoros is the second largest city in the state of Tamaulipas.As of 2016, Matamoros had a population of 520,367.In addition, the Matamoros–Brownsville Metropolitan Area has a population of 1,387,985, making it the 4th largest metropolitan area on the Mexico–US border. Matamoros is the 39th largest city in Mexico and anchors the second largest metropolitan area in Tamaulipas.

The economy of the city is significantly based on its international trade with the United States through the USMCA agreement, and it is home to one of the most promising industrial sectors in Mexico, mainly due to the presence of maquiladoras. In Matamoros, the automotive industry hosts the assembly and accessories plants for brands such as General Motors, Ford, Chrysler, BMW, and Mercedes-Benz. Prior to the growth of the maquiladoras in the 2000s, Matamoros' economy had historically been principally based on agriculture, since northern Mexico's biggest irrigation zones are in the municipality. PEMEX announced a multibillion-peso offshore drilling project for the port of Matamoros, one of the future prospects for Mexico's oil industry.

Starbase, formerly Boca Chica Village or Kopernik Shores, is a city in Cameron County, Texas, United States, near the mouth of the Rio Grande. It lies 20 miles (32 km) east of the City of Brownsville on the Boca Chica peninsula, and forms part of the Brownsville–Harlingen–Raymondville and the Matamoros–Brownsville metropolitan areas. It is situated on State Highway 4, (SH 4, Boca Chica Boulevard), immediately south of the South Bay lagoon, and is located about 2 mi (3.2 km) north of the mouth of the Rio Grande. The population was 500 as of 2025.

The town was initially formed in the late 1960s, and has changed greatly since 2018 as SpaceX came to purchase many of the properties in the village. Numerous construction projects are underway including a community center, school, clinic, and additional housing. In 2014, the village was chosen as the location for the construction of a control facility for the SpaceX South Texas launch site, while the launch site itself was slated to be built just 2 miles (3.2 km) farther east, adjacent to Boca Chica State Park on the Texas Gulf Coast. Flight testing—and even more frequent ground testing—of prototype rocket vehicles and rocket engines began in 2019 and have continued into 2025.