03602 -- U.S. ZIP code Municipality (1990): ALSTEAD, New Hampshire All ZIPs for this municipality (1990): 03602 Population (2000): 2128 Housing Units (2000): 1032 Land area (2000): 48.610689 sq. miles (125.901102 sq. km) Water area (2000): 0.545865 sq. miles (1.413783 sq. km) Total area (2000): 49.156554 sq. miles (127.314885 sq. km) Located within: New Hampshire (NH) Location: 43.142384 N, 72.325755 W