20772 -- U.S. ZIP code Municipality (1990): UPPER MARLBORO, Maryland All ZIPs for this municipality (1990): 20772 Population (2000): 35414 Housing Units (2000): 13055 Land area (2000): 75.757735 sq. miles (196.211625 sq. km) Water area (2000): 0.077595 sq. miles (0.200970 sq. km) Total area (2000): 75.835330 sq. miles (196.412595 sq. km) Located within: Maryland (MD) Location: 38.792281 N, 76.781009 W