Allendale -- U.S. County in South Carolina Population (2000): 11211 Housing Units (2000): 4568 Land area (2000): 408.200432 sq. miles (1057.234221 sq. km) Water area (2000): 4.379531 sq. miles (11.342932 sq. km) Total area (2000): 412.579963 sq. miles (1068.577153 sq. km) Located within: South Carolina (SC), FIPS 45 Location: 32.994024 N, 81.324531 W Headwords: Allendale Allendale, SC Allendale County Allendale County, SC