Arecibo, Puerto Rico, United States [ZonaUrbana]; population was 49,545 in 1990; housing units was 17,350 in 1990; location is 18°27'N 66°44'W; land area is 15.37 square miles (9,839 acres); water area is 2.66 square miles (1,704 acres); FIPS code is 3368 [SourceCBP]