town, Vizcaya provincia (province), in the comunidad autónoma (autonomous community) of the Basque Country, northern Spain. The town, a northwestern suburb of Bilbao, lies at the mouth of the Nervión River, on the western side of Bilbao Bay. It was founded in 1322 by María Díaz de Haro, wife of the infante Don Juan, prince of Castile, and was named for its function as a portus galorum (Latin: “galley-slave port”). The town's Gothic church of Santa María dates from the 13th century.

Portugalete has metalworks, a boiler factory, and a soybean-processing plant. It is linked to the barrio of Las Arenas (Getxo) on the opposite shore of the Nervión estuary by a lofty suspension bridge, Vizcaya Bridge, built (1893) by Alberto Palacio; in 2006 the bridge was designated a UNESCO World Heritage site. Much of the town's industry has merged with that of Bilbao. Pop. (2007 est.) mun., 48,386.