Allen -- U.S. County in Indiana Population (2000): 331849 Housing Units (2000): 138905 Land area (2000): 657.249713 sq. miles (1702.268870 sq. km) Water area (2000): 2.852899 sq. miles (7.388974 sq. km) Total area (2000): 660.102612 sq. miles (1709.657844 sq. km) Located within: Indiana (IN), FIPS 18 Location: 41.090284 N, 85.100068 W Headwords: Allen Allen, IN Allen County Allen County, IN