64640 -- U.S. ZIP code Municipality (1990): GALLATIN, Missouri All ZIPs for this municipality (1990): 64640 Population (2000): 3185 Housing Units (2000): 1697 Land area (2000): 150.795323 sq. miles (390.558077 sq. km) Water area (2000): 0.089775 sq. miles (0.232515 sq. km) Total area (2000): 150.885098 sq. miles (390.790592 sq. km) Located within: Missouri (MO) Location: 39.912973 N, 93.965365 W