64620 -- U.S. ZIP code Municipality (1990): ALTAMONT, Missouri All ZIPs for this municipality (1990): 64620 Population (2000): 461 Housing Units (2000): 216 Land area (2000): 22.112078 sq. miles (57.270016 sq. km) Water area (2000): 0.016187 sq. miles (0.041925 sq. km) Total area (2000): 22.128265 sq. miles (57.311941 sq. km) Located within: Missouri (MO) Location: 39.900508 N, 94.088769 W