South Portland, city (1990 pop. 23,163), Cumberland co., SW Maine, on the Fore River and Casco Bay, part of the Portland metropolitan area; separated from Falmouth (now Portland) as part of the town of Cape Elizabeth 1765, separated from Cape Elizabeth and inc. 1898. Ships have been built there since the 17th cent. The city also produces varied light manufactures and is a wholesale and retail trade center. The area was settled c.1633. Fort Preble (now Fort Williams) was built in Cape Elizabeth before the War of 1812. Portland Head Light, near the fort in Cape Elizabeth, is the oldest lighthouse (1791) on the Maine coast. The Univ. of Southern Maine is there.