Portland, IN -- U.S. city in Indiana Population (2000): 6437 Housing Units (2000): 2928 Land area (2000): 4.108272 sq. miles (10.640375 sq. km) Water area (2000): 0.006559 sq. miles (0.016988 sq. km) Total area (2000): 4.114831 sq. miles (10.657363 sq. km) FIPS code: 61236 Located within: Indiana (IN), FIPS 18 Location: 40.433884 N, 84.979914 W ZIP Codes (1990): 47371 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Portland, IN Portland