 Route 27 interchanges with U.S. Route 22 and immediately passes under Interstate 78.Route 27 continues north, passing under railroad tracks carrying Conrail Shared Assets Operations' Lehigh Line and NJ Transit's Raritan Valley Line and crossing Conrail Shared Assets Operations' Poinier Street Lead line/Irvington-Hillside Industrial Branch at-grade, before it comes to an intersection with Poinier Street, where the route heads east along that road to its northern terminus at an interchange with Route 21 and Broad Street.The southern part of Route 27 follows the Lenape Assunpink Trail that during the colonial era was known as the Old Dutch Trail, and later became the Kings Highway.