Allendale, IL -- U.S. village in Illinois Population (2000): 528 Housing Units (2000): 205 Land area (2000): 0.300771 sq. miles (0.778992 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 0.300771 sq. miles (0.778992 sq. km) FIPS code: 00815 Located within: Illinois (IL), FIPS 17 Location: 38.528524 N, 87.709811 W ZIP Codes (1990): 62410 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Allendale, IL Allendale