McElhattan is a census-designated place in Wayne Township in southern Clinton County, Pennsylvania, United States. As of the 2010 census, the population was 598.The community is located in eastern Clinton County and is bordered to the northwest by the West Branch of the Susquehanna River and to the southeast by U.S. Route 220, a four-lane freeway. The southwestern part of the CDP includes the area known as Youngdale.