Padre Island is the largest of the Texas barrier islands as well as the world's longest barrier island. It is part of the U.S. state of Texas. The island is located on Texas' southern coast of the Gulf of Mexico and is famous for its white sandy beaches at the south end. The name of the island means Father in Spanish, after Father José Nicolás Ballí (c.1770-1829), who served as collector of finances for all the churches in the Rio Grande Valley and founded the first mission in present Cameron County.

Padre Island is the second largest island by area in the contiguous United States, after Long Island. It is about 113 miles (182 km) long and 1.8 miles (3 km) wide, stretching from the city of Corpus Christi, in the north, to the resort community of South Padre Island in the south. The island is oriented north-south, with the Gulf of Mexico on the east, and Laguna Madre on the west. The island's northern end connects to Mustang Island by roadway. The southern end of the island is separated from Brazos Island by the Brazos Santiago Pass.