sentences:  PA 645 begins at an intersection with US 422 at the north edge of the borough of Myerstown in Lebanon County, where North Locust Street heads south into Myerstown.From this intersection, the route heads north on two-lane undivided North Locust Street into Jackson Township, passing near residential neighborhoods.PA 645 runs through agricultural areas with some homes, curving northwest briefly before turning north again onto Kutztown Road.