Route 505 begins at County Route 501 in Union City, where it travels east and soon aftering entering Weehawken, it is named Boulevard East. It proceeds northward, traveling parallel to the Hudson River atop the Hudson Palisades. At Hillside Road in West New York it takes a right turn and descends to the waterfront becoming River Road. It then intersects Route 5 before intersecting Interstate 95. Route 505 then intersects the Palisades Interstate Parkway, before traveling parallel to it. It then intersects County Route 501, before turning due north from the westward path it had previously followed along. It travels by Morrow Park, shortly before traveling near the Knickerbocker Country Club. It then intersects County Route 70, before continuing north and intersecting County Route 502. From there, it proceeds north, reaching its end at the New York/New Jersey border.