Elizabeth is a borough in Allegheny County, Pennsylvania, United States, on the east bank of the Monongahela River, where Pennsylvania Route 51 crosses, 15 miles upstream of Pittsburgh and close to the county line. The population was 1,398 at the 2020 census. The borough of Elizabeth is entirely contained within the 15037 USPS ZIP code. The local school district is the Elizabeth Forward School District. The borough is home to neighborhoods Walker Heights and Town Hill.