Padre Island in the context of "Sand dunes"

Barrier islands are a coastal landform, a type of dune system and sand island, where an area of sand off the coast has been formed by wave and tidal action parallel to the mainland coast. They usually occur in chains, consisting of anything from a few islands to more than a dozen, and are subject to change during storms and other action. They protect coastlines by absorbing energy, and create areas of protected waters where wetlands may flourish. A barrier chain may extend for hundreds of kilometers, with islands periodically separated by tidal inlets. The longest barrier island in the world is Padre Island of Texas, United States, at 113 miles (182 km) long. Sometimes an important inlet may close permanently, transforming an island into a barrier peninsula, often including a barrier beach. Though many are long and narrow, the length and width of barriers and overall morphology of barrier coasts are related to parameters including tidal range, wave energy, sediment supply, sea-level trends, and basement controls. The amount of vegetation on the barrier has a large impact on the height and evolution of the island.

There are chains of barrier islands along approximately 13 to 15% of the world's coastlines. They display different settings, suggesting that they can form and be maintained in a variety of environments. Numerous theories have been proposed to explain their formation.

The Texas barrier islands are a chain of barrier islands in the Gulf of Mexico along the Texas Gulf Coast. The islands enclose a series of estuaries along the Texas coast and attract tourists for activities such as recreational fishing and dolphin watching. The seven barrier islands, listed from northeast to southwest, are Galveston Island, Follet's Island, Matagorda Island, San José Island, Mustang Island, Padre Island, and Brazos Island.

Padre Island is the world's largest barrier island, with a length of 113 miles (182 km). Since 1962 Padre Island has been divided in two by the dredging of the Port Mansfield Channel roughly 30 miles (48 km) north of the south end of the island, which separated it into portions referred to as South Padre Island and North Padre Island.

Padre Ballí (ca. 1770–1829), also known as José Nicolás Ballí, was a rancher, a priest, and an original grantee of Padre Island, which was named after him. However, when he owned the island, it was known as the Isla de Santiago land grant. Padre Island had been granted to his grandfather, Nicolás Ballí, in 1759 by King Charles III of Spain, and Padre Ballí requested a clear title to the property in 1827. His mother Rosa María Hinojosa de Ballí had made a joint application with Padre for eleven leagues of the island, but when reapplication was required in 1800, she withdrew her name in favor of him.

The Laguna Madre is a long, shallow, hypersaline lagoon along the western coast of the Gulf of Mexico in Nueces, Kenedy, Kleberg, Willacy and Cameron Counties in Texas, United States. It is one of seven major estuaries along the Gulf Coast of Texas. The roughly 20-mile (32 km) long Saltillo Flats land bridge divides it into Upper and Lower lagoons joined by the Intracoastal Waterway, which has been dredged through the lagoon. Cumulatively, Laguna Madre is approximately 130 miles (210 km) long, the length of Padre Island in the US. The main extensions include Baffin Bay in Upper Laguna Madre, Red Fish Bay just below the Saltillo Flats, and South Bay near the Mexican border. As a natural ecological unit, the Laguna Madre of the United States is the northern half of the ecosystem as a whole, which extends into Tamaulipas, Mexico approximately 144 miles (232 km) south of the US border, to the vicinity of the Rio Soto La Marina and the town of La Pesca, extending approximately 275 miles (443 km) through USA and Mexico in total.

The lagoon's ecosystem is protected by the Laguna Atascosa National Wildlife Refuge and the Padre Island National Seashore, as well as the privately owned King Ranch. The human history predates the formation of the Laguna Madre, and settlements have been established at Port Isabel and Port Mansfield on the lagoon's shores.

Mustang Island is a barrier island on the Gulf Coast of Texas in the United States. The island is 18 miles (29 km) long, stretching from Corpus Christi to Port Aransas. The island is oriented generally northeast–southwest, with the Gulf of Mexico on the east and south, and Corpus Christi Bay on the north and west. The island's southern end connects by roadway to Padre Island. At the northern end of the island is Port Aransas, beyond which is San José Island. The Aransas Channel, also known as the "Aransas Pass", which separates Mustang Island from San José Island, is protected by jetties extending into the Gulf from each island.

The town of Port Aransas is located at the northern end of the island. Mustang Island State Park encompasses the entire southern third of the island, including 3,955 acres (1,600 ha) and 5 miles (8 km) of beach. The city of Corpus Christi includes the northernmost portion of Padre Island and part of Mustang Island between Port Aransas and the state park.

Brazos Island, also known as Brazos Santiago Island, is a barrier island on the Gulf Coast of Texas in the United States, south of the town of South Padre Island and north of the city of Starbase. The island is located in Cameron County.

Brazos Santiago Pass partitions the barrier islands of Brazos Island and Padre Island in the Lower Rio Grande Valley.