 As of the 2010 U.S. Census the micropolitan area ranked 16th most populous in the State of Pennsylvania and the 315th most populous in the United States with a population of 39,238.Clinton County is also a part of the Williamsport-Lock Haven, PA Combined Statistical Area (CSA), which combines the population of both Clinton County and the Lycoming County areas.The Combined Statistical Area ranked 11th in the State of Pennsylvania and 143rd most populous in the United States with a population of 155,349.