Plymouth, IN -- U.S. city in Indiana Population (2000): 9840 Housing Units (2000): 4100 Land area (2000): 6.958942 sq. miles (18.023576 sq. km) Water area (2000): 0.014506 sq. miles (0.037571 sq. km) Total area (2000): 6.973448 sq. miles (18.061147 sq. km) FIPS code: 60822 Located within: Indiana (IN), FIPS 18 Location: 41.343894 N, 86.312544 W ZIP Codes (1990): Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Plymouth, IN Plymouth