 Pennsylvania Route 3 westbound follows Walnut Street from 38th Street (U.S. Route 13) to its western terminus at the Cobbs Creek Parkway.It is most known for Rittenhouse Square Park and its upscale shopping district in the high-end neighborhood of the same name.The majority of designer and fast fashion stores located on Walnut Street are situated on a four-block stretch between Broad Street and 18th Street, which is anchored by the park on the southwest corner.