61873 -- U.S. ZIP code Municipality (1990): SAINT JOSEPH, Illinois All ZIPs for this municipality (1990): 61873 Population (2000): 5020 Housing Units (2000): 1945 Land area (2000): 67.185723 sq. miles (174.010217 sq. km) Water area (2000): 0.217935 sq. miles (0.564448 sq. km) Total area (2000): 67.403658 sq. miles (174.574665 sq. km) Located within: Illinois (IL) Location: 40.124202 N, 88.034010 W