Marquesas Islands, pair of volcanic archipelagoes in French Polynesia in the central South Pacific Ocean, 740 miles (1,200 km) northeast of Tahiti. The islands are, for the most part, high and craggy, with jagged peaks rising in places to some 4,000 feet (1,200 metres). The largest (77 square miles [200 square km]) and most populated island of the southeastern group is Hiva Oa, the burial place of the French artist Paul Gauguin and the Belgian singer Jacques Brel; the group also includes Fatu Hiva and Tahuata, each about 23 square miles (60 square km) in area, and the uninhabited Motane and Fatu Huku. The northwestern group comprises Nuku Hiva, Ua Pou, Ua Huka, Eiao, and Hatutu.
The Marquesas are believed to have been inhabited as early as 340 bce, although there is disagreement among scholars regarding the origin of the settlers. The southeastern islands were sighted in 1595 by the Spanish explorer Álvaro de Mendaña de Neira, who named them for his patron, the marqués de Mendoza, viceroy of Peru. The British naval captain James Cook visited Fatu Huku in 1774. In 1791 the American sea captain Joseph Ingraham sighted the northwestern group and named them Washington Islands. The whole group, annexed by the French in 1842, now forms an administrative subdivision of French Polynesia, with headquarters at Hakapehi (Tai-o-hae) on Nuku Hiva.
Because the islands lack coastal plains and coral reefs, habitation is largely restricted to the narrow valleys where streams run down from the mountains. Chief agricultural products are copra, taro, breadfruit, coffee, and vanilla. Tourism is a developing industry, and the islands are popular with cruising yachts. Most of the residents are Roman Catholic. The Marquesas Islands were designated a UNESCO World Heritage site in 2024. Total land area (including inland water area) 405 square miles (1,049 square km). Pop. (2017) 9,346.