Post Falls, ID -- U.S. city in Idaho Population (2000): 17247 Housing Units (2000): 6697 Land area (2000): 9.656273 sq. miles (25.009631 sq. km) Water area (2000): 0.045304 sq. miles (0.117337 sq. km) Total area (2000): 9.701577 sq. miles (25.126968 sq. km) FIPS code: 64810 Located within: Idaho (ID), FIPS 16 Location: 47.715552 N, 116.937926 W ZIP Codes (1990): 83854 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Post Falls, ID Post Falls