Aveiro, a seaport, episcopal see, and the capital of an administrative district, formerly included in the province of Beira, Portugal; on the river Vouga, and the Lisbon-Oporto railway. Pop. (1900) 9979. Aveiro is built on the southern shore of a marshy lagoon, containing many small islands, and measuring about 15 m. from north to south, with an average breadth of about 1 m. The Barra Nova, an artificial canal about 33 ft. deep, was constructed between 1801 and 1808, and gives access to the Atlantic ocean. The local industries include the preparation of sea-salt, the catching and curing of fish, especially sardines and oysters, and the gathering of aquatic plants (moliço). There is also a brisk trade in wine, oil and fruit; while the Aveiro district contains copper and lead mines, besides much good pasture-land.
Aveiro is probably the Roman Talabriga. In the 16th century it was the birthplace of João Affonso, one of the first navigators to visit the fishing-grounds of Newfoundland; and it soon became famous for its fleet of more than sixty vessels, which sailed yearly to that country, and returned laden with dried codfish. During the same century the cathedral was built, and the city was made a duchy. The title "duke of Aveiro" became extinct when its last holder, Dom José Mascarenhas e Lancaster, was burned alive for high treason, in 1759. The administrative district of Aveiro coincides with the north-western part of the province of Beira; pop. (1900) 303,169; area, 1065 sq. m.