15431 -- U.S. ZIP code Municipality (1990): DUNBAR, Pennsylvania All ZIPs for this municipality (1990): 15431 Population (2000): 5386 Housing Units (2000): 2322 Land area (2000): 51.015687 sq. miles (132.130017 sq. km) Water area (2000): 0.000034 sq. miles (0.000089 sq. km) Total area (2000): 51.015721 sq. miles (132.130106 sq. km) Located within: Pennsylvania (PA) Location: 39.968368 N, 79.618159 W