I-78 highlighted in red
|Maintained by PennDOT and DRJTBC|
|Length||75.23 mi (121.07 km)|
|West end||I-81 In Union Township|
| US 22 from Union Township to Upper Macungie Township|
PA 501 in Bethel
PA 183 near Strausstown
PA 61 near Hamburg
PA 100 in Fogelsville
PA 309 from Dorneyville to Summit Lawn
US 222 / PA 222 near Dorneyville
PA 29 near Allentown
PA 33 in Lower Saucon Township
|East end||I-78 at the New Jersey state line in Williams Township|
|Counties||Lebanon, Berks, Lehigh, Northampton|
Interstate 78 (I-78) is an east–west Interstate Highway stretching from Union Township in Lebanon County, Pennsylvania to New York City. In the U.S. state of Pennsylvania, I-78 runs for about 77 miles (124 km), from the western terminus at I-81 in Union Township, Lebanon County to the New Jersey state line near Easton, Northampton County.
I-78 starts in Pennsylvania at an interchange with I-81. It merges with U.S. Route 22 in Lebanon County, with the median strip becoming narrow at that point; the two run together for 43 miles (69 km) from Bethel Township to Kuhnsville. Near Hamburg at exit 29, the highway meets Pennsylvania Route 61. At exit 51 near Kuhnsville, US 22 splits off from I-78 and becomes the Lehigh Valley Thruway. At exit 53, Pennsylvania Route 309 merges with I-78 for 7 miles (11 km). Dorney Park & Wildwater Kingdom is visible from the freeway approaching exit 54 for U.S. Route 222, which leads to the park. In Summit Lawn, State Route 309 leaves the freeway toward Quakertown at exit 60, with prior exit 59 providing access to Pennsylvania Route 145. Past Allentown and Bethlehem, Pennsylvania Route 33 meets I-78 at exit 71, providing access to the Pocono Mountains to the north. The last exit in Pennsylvania is Exit 75/Morgan Hill Road, which connects to Pennsylvania Route 611. The Interstate crosses the Delaware River on the Interstate 78 Toll Bridge, leaving Pennsylvania for New Jersey. Tolls are only required on the westbound side, coming into Pennsylvania.
Interstate 78 carries some additional name designations throughout Pennsylvania. In Lebanon County, Interstate 78 is known as the 78th Division Highway. In Berks County between mile marker 23 and mile marker 35, Interstate 78 is known as the CMSgt. Richard L. Etchberger Memorial Highway, in honor of Richard Etchberger. In Lehigh and Northampton counties, Interstate 78 is known as the Walter J. Dealtrey Memorial Highway. The portion concurrent with US Route 22 shares its designation of the William Penn Highway.
Construction of the freeway between Lebanon and Lehigh counties took place between 1950 and 1970, originally as an upgraded alignment of US 22. All of I-78 was completed by 1989. When the Interstate Highway System numbers were first assigned in 1957, the route was planned as I-80N. Prior to the late 1960s, I-78 was to be routed on the Lehigh Valley Thruway across to Phillipsburg, New Jersey, continuing the concurrency with US 22; however, because of heavy opposition by residents of Phillipsburg, PennDOT and NJDOT opted to build the new southerly alignment on which I-78 is routed today.
Interstate 178 was a proposed spur from Interstate 78, but was cancelled because the Liberty Bell Shrine was in the path of the proposed expressway. Additionally, locals opposed the destruction of Sixth and Seventh Streets to accommodate the highway. The planned northern terminus would have been between the 15th Street and PA 145 interchanges. If built, Interstate 178 would have connected US 22, formerly designated I-78 into Allentown.
Interstate 378 was the designation for a spur route that would extend from Interstate 78 into Bethlehem. At the time, I-78 was designated as the Lehigh Valley Thruway, concurrent with US 22, and the route numbering made sense. Unlike I-178, the route was built. When I-78 was later redirected south of this area, I-378 had no direct connection to I-78 and therefore was downgraded to state route status. The route still remains, as a freeway with exits and their own numbers.
When Interstate 178 and 378 were planned (and 378 was built), I-78 ran the length of the Lehigh Valley Thruway. Later, I-78 was rerouted onto a bypass route south of the Thruway. This was due to opposition to continue the concurrency with the Thruway into New Jersey.
In 2013, PennDOT announced plans to improve a portion of I-78 in eastern Berks County. The project will redesign the PA 737 interchange, add truck lanes, widen lanes and shoulders, and raise the height of three overpasses. Construction began in 2015 and is planned to be completed in 2025 at a cost of $412.6 million.
|Lebanon||Union Township||0.00||0.00||���||1B||I-81 south – Harrisburg||Exit 89 on I-81|
|0.55||0.89||–||1A||I-81 north – Hazleton|
|Bethel Township||5.85||9.41||1||6||PA 343 south – Lebanon, Fredericksburg||Eastbound exit and westbound entrance;|
northern terminus of PA 343
|7.90||12.71||1||8||US 22 west to PA 343 – Lebanon, Fredericksburg||West end of concurrency with US 22;|
westbound exit and eastbound entrance
|Berks||Bethel Township||10.21||16.43||2||10||PA 645 – Frystown|
|Bethel||12.68||20.41||3||13||PA 501 – Bethel|
|Bethel Township||14.67||23.61||4||15||Grimes||Access via Court Street (eastbound) and Frantz Road (westbound)|
|15.40||24.78||5||16||Midway||Access via Midway Road; access to Conrad Weiser Homestead|
|16.58||26.68||6||17||PA 419 – Rehrersburg|
|Strausstown||18.65||30.01||7||19||PA 183 – Strausstown|
|Upper Bern Township||22.71||36.55||8||23||Shartlesville||Access via Mountain Road|
|9||29||PA 61 – Reading, Pottsville||Signed as exits 29A (south) and 29B (north) westbound|
|Hamburg||30.19||48.59||10||30||Hamburg||Access via North 4th Street|
|Greenwich Township||35.23||56.70||11||35||PA 143 – Lenhartsville|
|40.27||64.81||12||40||PA 737 – Kutztown, Krumsville||Access to Kutztown University|
|Lehigh||Weisenberg Township||44.96||72.36||13||45||PA 863 – Lynnport, New Smithville|
|Upper Macungie Township||49.26–|
|14||49||PA 100 – Trexlertown, Fogelsville||Split into exits 49A (south) and 49B (north)|
US 22 east to I-476 / Penna Turnpike NE Extension / PA 309 north – LVI Airport
|East end of concurrency with US 22;|
eastbound exit and westbound entrance
|South Whitehall Township||53.67||86.37||–||53|
PA 309 north to I-476 / Penna Turnpike NE Extension – Tamaqua
|West end of concurrency with PA 309;|
westbound exit and eastbound entrance
|16||54||US 222 south / PA 222 north (Hamilton Boulevard)||Signed as exits 54A (south) and 54B (north) westbound; access to Reading and Dorney Park & Wildwater Kingdom|
|Salisbury Township||55.41||89.17||17||55||PA 29 (Cedar Crest Boulevard)|
|57.63||92.75||18B||58||Emaus Avenue south||Westbound exit only|
|Upper Saucon Township||58.83||94.68||19||59||To PA 145 – Summit Lawn||Eastbound exit and westbound entrance; access via Rock Road|
|59.92||96.43||20A||60A||PA 309 south – Quakertown||East end of concurrency with PA 309;|
signed as exit 60 eastbound
|60.30||97.04||20B||60B||PA 145 north (South 4th Street)||Westbound exit only|
|Northampton||Hellertown||66.36||106.80||21||67||PA 412 – Hellertown, Bethlehem||Access to Lehigh University and Wind Creek Bethlehem|
|Lower Saucon Township||71.04||114.33||--||71||PA 33 north to US 22 – Stroudsburg||Southern terminus of PA 33; access to Pocono Mountains and Lehigh Valley Airport|
|Williams Township||75.00||120.70||22||75||To PA 611 – Easton, Philadelphia||Access via Cedarville Road|
|Rest Area and Welcome Center (westbound only)|
|Delaware River Toll Plaza|
(E-ZPass or cash, westbound only)
|Delaware River||77.10||124.08||Interstate 78 Toll Bridge|
|–||–||I-78 east – New York City||Continuation into New Jersey|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|
- "Route Log - Main Routes of the Eisenhower National System Of Interstate and Defense Highways - Table 1". Federal Highway Administration. Retrieved 4 October 2014.
- Steve Esack (2004-01-30). "Section of I-78 named to honor businessman Walter J. Dealtrey - Morning Call". Articles.mcall.com. Retrieved 2013-01-29.
- Official Route Numbering for the National System of Interstate and Defense Highways (Map). American Association of State Highway Officials. August 14, 1957. Retrieved January 3, 2017.
- "Interstate-Guide: Interstate 78". www.interstate-guide.com. Retrieved March 26, 2016.
- "Pennsylvania's Dearly Departed Interstates".
- "I-178 (cancelled) Pennsylvania".
- "1963 Rand McNally".
- "I-178 Map".
- Devlin, Ron (January 18, 2013). "PennDOT unveils upgrade to Interstate 78". Reading Eagle. Retrieved January 18, 2013.
- Winfrey, Katiera; Wivell, Dawn (March 7, 2019). "PennDOT, Berks Planning Commission provide update on I-78". 69 News. Retrieved March 16, 2019.
- Calculated using DeLorme Street Atlas USA 2007
- "Pennsylvania Exit Numbering" (PDF). Pennsylvania Department of Transportation. Retrieved October 2, 2007.
|Wikimedia Commons has media related to Interstate 78 in Pennsylvania.|
- Interstate 78 exits in Pennsylvania
- Steve Anderson's PhillyRoads.com: Allentown Spur Route (unbuilt I-178)
- Steve Anderson's PhillyRoads.com: Bethlehem Spur Route (PA 378, former I-378)