Onaga, KS -- U.S. city in Kansas Population (2000): 704 Housing Units (2000): 347 Land area (2000): 0.634695 sq. miles (1.643853 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 0.634695 sq. miles (1.643853 sq. km) FIPS code: 52875 Located within: Kansas (KS), FIPS 20 Location: 39.489415 N, 96.168993 W ZIP Codes (1990): 66551 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Onaga, KS Onaga