Elizabeth is a borough in Allegheny County, Pennsylvania, on the east bank of the Monongahela River, where Pennsylvania Route 51 crosses, 15miles (24km) upstream (south) of Pittsburgh and close to the county line. The population was 1,493 at the 2010 census. The borough of Elizabeth is entirely contained within the 15037 USPS ZIP code. According to the United States Census Bureau, the borough has a total area of 0.4square miles (1.0Square kilometers), of which 0.3square miles (0.78Square kilometer) is land and 0.1square miles (0.26Square kilometer), or 14.63%, is water. As of the census of 2000, there were 1,609people, 681households, and 422families residing in the borough. The population density was 4,544.8people per square mile (1,775.0Square kilometers). There were 758housing units at an average density of 2,141.1per square mile (836.2Square kilometers).