Yardley is a borough in Bucks County, Pennsylvania, United States. Yardley borders the Delaware River and Ewing Township, New Jersey to its east and Lower Makefield Township to its north, west, and south. The United States Post Office assigns many addresses in Lower Makefield Township the preferred city of "Yardley", although they are outside the borough. As of the 2020 census, Yardley had a population of 2,605. Yardley is part of the Philadelphia metropolitan area.