Countryside, IL -- U.S. city in Illinois Population (2000): 5991 Housing Units (2000): 2818 Land area (2000): 2.690473 sq. miles (6.968292 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 2.690473 sq. miles (6.968292 sq. km) FIPS code: 16873 Located within: Illinois (IL), FIPS 17 Location: 41.778885 N, 87.874006 W ZIP Codes (1990): Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Countryside, IL Countryside