Interstate 476, a spur of Interstate 76, is made up of two components: the non-tolled Mid-County Expressway ("Blue Route"), running between Interstate 95 near Chester and the eastern portion of the mainline Pennsylvania Turnpike (Interstate 276) near Plymouth Meeting in greater Philadelphia, intersecting its parent in the interim, and the 111-mile Northeast Extension of the turnpike, passing through the Lehigh Valley and a portion of the Pocono Mountains en route to a northern terminus at Interstate 81 outside of Scranton. The Northeast Extension formerly bore the designation of Pennsylvania Route 9, and includes the Lehigh Tunnel under the Blue Mountain north of Allentown.