Île-à-Vache, (French, also expressed Île-à-Vaches, former Spanish name Isla Vaca, all translate to Cow Island) is a Caribbean island, one of Haiti's satellite islands. It lies in the Baie de Cayes about 6.5 miles (10.5 km) off the coast of the country's southwest peninsula, roughly between the town of Les Cayes and Pointe l'Abacou. It was formerly known by the name of Abacca. Administratively, it became a commune in 1976 as part of the Les Cayes Arrondissement in the Sud Department.
Île-à-Vache was claimed by the Spanish Empire in 1492 as part of Hispaniola, and for the next two centuries it was known by the name Isla Vaca. In 1697 the island of Hispaniola was formally divided between Spain and France in the Treaty of Ryswick which ended the Nine Years War. France assumed control of the western half of Hispaniola and named it Saint-Domingue, and Isla Vaca took on its current name, Île-à-Vache.
The island is about 8 miles (13 km) long and 2 miles (3.2 km) wide, with an area of 20 square miles (52 km2). The western end of the island has rolling hills with elevations as high as 490 feet (150 m) with several small swamps in the valleys; the eastern side of the island is swampy, and contains a lagoon with one of the largest mangrove forests in Haiti. The island is also surrounded by several dangerous shoals, reefs, and rocks that have been the cause of many shipwrecks throughout history, including that of the famous Canadian fishing and racing schooner Bluenose, which was wrecked on the island in 1946.
The pirate captain Henry Morgan (c.1635–1688) frequently used the little island as a base for his operations. Morgan planned and staged many of his largest raids from Isla Vaca, and lost multiple ships in the island's waters which have recently been found and explored by research divers.
The government has built a 2.6-kilometre runway with plans for an international airport.