Guayanilla -- U.S. Municipio in Puerto Rico Population (2000): 23072 Housing Units (2000): 8147 Land area (2000): 42.361847 sq. miles (109.716676 sq. km) Water area (2000): 21.949372 sq. miles (56.848611 sq. km) Total area (2000): 64.311219 sq. miles (166.565287 sq. km) Located within: Puerto Rico (PR), FIPS 72 Location: 18.038866 N, 66.791684 W Headwords: Guayanilla Guayanilla, PR Guayanilla Municipio Guayanilla Municipio, PR