Mehlville, Missouri, United States [CDP]; population was 27,557 in 1990; housing units was 12,078 in 1990; location is 38°30'N 90°19'W; land area is 7.39 square miles (4,727 acres); water area is 0.21 square miles (133 acres); FIPS code is 47180 [SourceCBP]