61603 -- U.S. ZIP code Municipality (1990): PEORIA HEIGHTS, Illinois All ZIPs for this municipality (1990): 61603 61614 Population (2000): 19433 Housing Units (2000): 8213 Land area (2000): 4.367609 sq. miles (11.312056 sq. km) Water area (2000): 0.003913 sq. miles (0.010134 sq. km) Total area (2000): 4.371522 sq. miles (11.322190 sq. km) Located within: Illinois (IL) Location: 40.712887 N, 89.579047 W