Pennsylvania Route 664 (designated by the Pennsylvania Department of Transportation as SR 0664) is a 17.59-mile-long (28.31 km) state highway located in Clinton and Lycoming counties in Pennsylvania. The southern terminus is at State Route 120 in Lock Haven, while the northern terminus is at State Route 44 on the Clinton-Lycoming county line in the community of Haneyville. The route passes through small communities, but does not intersect with any other legislated highways in the area.