 At the Laurel Avenue intersection, PA 73 becomes Cottman Avenue and turns into a three-lane road with one eastbound lane and two westbound lane that forms the border between the city of Philadelphia in Philadelphia County to the northeast and Cheltenham Township in Montgomery County to the southwest.The route passes between Burholme Park in Philadelphia and homes in Cheltenham Township.The road passes more homes and fully enters Philadelphia upon passing under SEPTA's Fox Chase Line south of the Ryers station in the Ryers neighborhood.