Jessup is a borough in Lackawanna County, Pennsylvania, United States. The population was 4,532 at the 2020 census. Jessup is located at 41°28′16″N 75°33′44″W / 41.47111°N 75.56222°W. According to the United States Census Bureau, the borough has a total area of 6.75 square miles, of which 6.7 square miles is land and 0.05 square miles is water.