South Portland, city, Cumberland County, southwestern Maine, on Casco Bay, southeast of Portland; incorporated 1898. Shipping is the major industry. Portland Head Light (1791), the oldest lighthouse on the Maine coast, is here. The area was settled about 1633. Shipping began in the 17th century and greatly expanded during World War II (1939-1945). Population 22,712 (1980); 23,163 (1990); 23,324 (2000).
