 Interstate 476 | ||||||||||
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 I-476 highlighted in red | ||||||||||
| Route information | ||||||||||
| Auxiliary route of I-76 | ||||||||||
| Maintained by PennDOT and PTC | ||||||||||
| Length | 132.10 mi[1][2][3] (212.59 km) | |||||||||
| History | Established 1970 Completed on December 16, 1992[2] | |||||||||
| Tourist routes | Blue Route Scenic Byway | |||||||||
| NHS | Entire route | |||||||||
| Restrictions | No hazardous goods in Lehigh Tunnel | |||||||||
| Major junctions | ||||||||||
| South end |  I-95 in Woodlyn | |||||||||
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| North end |    I-81 / US 6 / US 11 near Clarks Summit | |||||||||
| Location | ||||||||||
| Country | United States | |||||||||
| State | Pennsylvania | |||||||||
| Counties | Delaware, Montgomery, Bucks, Lehigh, Carbon, Luzerne, Lackawanna | |||||||||
| Highway system | ||||||||||
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Interstate 476 (I-476) is a 132.1-mile (212.6 km) auxiliary Interstate Highway of I-76 in the U.S. state of Pennsylvania. The highway runs from I-95 near Chester north to I-81 near Scranton, serving as the primary north–south Interstate corridor through eastern Pennsylvania. It consists of both the 20-mile (32 km) Mid-County Expressway, locally referred to as the "Blue Route", through Delaware and Montgomery counties in the suburban Philadelphia area, and the tolled, 110.6-mile (178.0 km) Northeast Extension of the Pennsylvania Turnpike, which connects the Delaware Valley with the Lehigh Valley, the Pocono Mountains, and the Wyoming Valley to the north.
The Mid-County Expressway passes through suburban areas, while the Northeast Extension predominantly runs through rural areas of mountains, forest, and farmland, with development closer to Philadelphia and in the Lehigh Valley and the Wyoming Valley. I-476 intersects many major roads, including I-76 (Schuylkill Expressway) in West Conshohocken, I-276 (Pennsylvania Turnpike) in Plymouth Meeting, U.S. Route 22 (US 22) near Allentown, and I-80 near Hickory Run State Park.
At its opening in 1979, I-476 was a three-mile-long (4.8 km), four-lane spur expressway connecting the Schuylkill Expressway with Chemical Road in Plymouth Meeting. The highway expanded the capacity for travel between King of Prussia, the Schuylkill Expressway, the Philadelphia Main Line, and Philadelphia suburbs to the city's north and in South Jersey. The highway was initially planned to connect down to I-95 in Delaware County. This portion of the highway opened in 1991.
In 1996, the I-476 designation was affixed to the preexisting Northeast Extension of the Pennsylvania Turnpike, replacing Pennsylvania Route 9 (PA 9). This was an older four-lane pre-Interstate limited-access highway that opened in sections between 1955 and 1957. Of earlier design, its cross section was very narrow, with only 4 feet (1.2 m) between opposing lanes of traffic in places. This extended I-476 north of Plymouth Meeting to Clarks Summit (near Scranton) as a part of the Pennsylvania Turnpike system. I-476 connected to the Northeast Extension at a state-of-the-art three-level interchange. This provided direct access to both I-276 east and I-476 north, now on the Northeast Extension.
With the redesignation of the Northeast Extension, I-476 surpassed I-495 in Massachusetts as the nation's longest auxiliary Interstate Highway. I-476 was widened to six lanes from the Mid-County Interchange to south of Quakertown between 2011 and 2020.
- ^ "Resurfacing" (PDF). I-476 Improvement Project. Pennsylvania Department of Transportation. Archived from the original (PDF) on June 15, 2007. Retrieved March 7, 2007.
- ^ a b Jeremy Rogoff; Mari A. Schaefer (June 10, 2007). "No remedy soon for a clogged Blue Route". The Philadelphia Inquirer. p. 2.
- ^ "Pennsylvania Turnpike Toll/Mileage Calculator". Pennsylvania Turnpike Commission. Retrieved March 7, 2007.