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port city, southeastern Sao Paulo estado (state), southeastern Brazil. It occupies an alluvial plain on the inner side of Sao Vicente Island, cut off from the mainland by a tidal channel. The city lies only a few feet above sea level, and its swampy island is drained by deep concrete conduits. The channel is free from obstructions, and in front of the city it widens into a bay deep enough for the largest oceangoing vessels. The docks are 4 miles (6 km) long and can accommodate about 50 ships at a time.