Long narrow inlet of the Gulf of Mexico along the shore of southern Texas, U.S., and northeastern Mexico.
Sheltered from the gulf by barrier islands, including Padre Island , it is divided into two sections by the delta of the Rio Grande ; the U.S. portion extends south for 120 mi (190 km) from Corpus Christi Bay, and the Mexican portion extends north for 100 mi (160 km) from the mouth of the Soto la Marina River. The Gulf Intracoastal Waterway runs through it.