Cartagena, port city, in the provincia and comunidad autónoma (“autonomous community”) of Murcia, southeastern Spain, . It is the site of Spain’s chief Mediterranean naval base. Its harbour, the finest on the east coast, is a deep, spacious bay dominated to seaward by four hills crowned with forts and approached by a narrow entrance guarded by batteries. The outer bay is sheltered by Escombrera Island.

It was founded in the 3rd century BC on the site of an ancient Iberian settlement by the Carthaginian general Hasdrubal. After its capture by Publius Cornelius Scipio (later surnamed Africanus) in 209 BC, it flourished as the Carthago Nova of the Romans. In 425 it was pillaged by the Goths. Cartagena was a bishopric from about 400 to 1289, when the see was removed to Murcia. Under the Moors it became an independent principality, which was destroyed by Ferdinand II of Castile in 1243, restored by the Moors, and finally conquered by James I of Aragon in 1269. Its easily defended natural harbour lent itself to rebuilding, and in the 16th century Philip II made it a great naval port. Cartagena was one of the focal points of the Carlist revolt in 1873–74. It was a Republican naval base during the Spanish Civil War of (1936–39).

Parts of the old town wall remain, as does the ruined Castillo de la Concepción, built in the 12th century on Roman foundations; the city’s archaeological museum contains Iberian, Greek, and Roman artifacts.

As a great commercial port, Cartagena was adversely affected during the early 20th century by the increasing importance of Barcelona, Málaga, and Alicante, all on the same coast. It Cartagena exports some olive oil, dried fruits, minerals (lead, zinc, silver, iron, copper, sulfur), and esparto fibre. Fewer minerals were exported after the opening of an independent port in 1898 at Portman, a mining village on a sheltered bay 11 miles (18 km) east. Cartagena has, however, important smelting works; its manufactures include glass and esparto fabrics. As a naval base, it has an arsenal and extensive dockyards. Pop. (1987 est.2001) city, 68,500; metropolitan area, 169,036184,686.