Interstate 78 in Pennsylvania

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Interstate 78 marker

Interstate 78
I-78 highlighted in red
Route information
Maintained by PennDOT & DRJTBC
Length75.23 mi[1] (121.07 km)
Major junctions
West end I-81 In Union Township
  US 22 in Union Township
PA 183 near Strausstown
PA 61 near Hamburg
PA 100 in Fogelsville
US 22 in Upper Macungie Township
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
CountiesLebanon, Berks, Lehigh, Northampton
Highway system
PA 77PA 78
PA 177I-178PA 178

Interstate 78 (I-78) is an east–west route 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 Interstate 81 in Union Township, Lebanon County to the New Jersey state line near Easton, Northampton County.

Route description[edit]

I-78 and US 22 eastbound in Berks County at mile marker 24.5.

I-78 starts in Pennsylvania at an interchange with Interstate 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.[2] 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.[3] In Lehigh and Northampton counties, Interstate 78 is known as the Walter J. Dealtrey Memorial Highway.[4] 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.[5] 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 Route 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.[6]

Interstate 178[edit]

Interstate 178
LocationAllentown, Pennsylvania

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.[7] If built, Interstate 178 would have connected US 22, formerly designated I-78 into Allentown.[8]

This route was shown in Rand McNally atlases in the late 1960s, but was not included in the 1971 federal interstate route log.[9] The route was supposed to end near Muhlenberg College.[10]

Interstate 378[edit]

Interstate 378
LocationBethlehem, Pennsylvania

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.

Improving I-78[edit]

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.[11] Construction began in 2015 and is planned to be completed in 2025 at a cost of $412.6 million.[12]

Exit list[edit]

CountyLocationmi[13]kmOld exit
New exit
LebanonUnion Township0.000.001B I-81 south – HarrisburgExit 89 on I-81
0.550.891A I-81 north – HazletonWestbound exit and eastbound entrance
Bethel Township5.859.4116 PA 343 – Lebanon, FredericksburgEastbound exit and westbound entrance;
northern terminus of PA 343
7.9012.7118 US 22 west to PA 343 – Lebanon, FredericksburgWest end of concurrency with US 22;
westbound exit and eastbound entrance
BerksBethel Township10.2116.43210 PA 645 – Frystown
Bethel12.6820.41313 PA 501 – Bethel
Bethel Township14.6723.61415GrimesAccess via Court Street (eastbound) and Frantz Road (westbound)
15.4024.78516MidwayAccess via Midway Road; access to Conrad Weiser Homestead
16.5826.68617 PA 419 – Rehrersburg
Strausstown18.6530.01719 PA 183 – Strausstown
Upper Bern Township22.7136.55823ShartlesvilleAccess via Mountain Road
Tilden Township29.11–
929 PA 61 – Reading, PottsvilleSigned as exits 29A (south) and 29B (north) westbound
Hamburg30.1948.591030HamburgAccess via North 4th Street
Greenwich Township35.2356.701135 PA 143 – Lenhartsville
40.2764.811240 PA 737 – Kutztown, KrumsvilleAccess to Kutztown University
LehighWeisenberg Township44.9672.361345 PA 863 – Lynnport, New Smithville
Upper Macungie Township49.26–
1449 PA 100 – Trexlertown, FogelsvilleSplit 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 Township53.6786.3753
PA 309 north to I-476 / Penna Turnpike NE Extension – Tamaqua
West end of concurrency with PA 309;
westbound exit and eastbound entrance
1654 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 Township55.4189.171755 PA 29 (Cedar Crest Boulevard)
Allentown57.2092.051857Lehigh Street
57.6392.7518B58Emaus Avenue southWestbound exit only
Upper Saucon Township58.8394.681959 To PA 145 – Summit LawnEastbound exit and westbound entrance; access via Rock Road
59.9296.4320A60A PA 309 south – QuakertownEast end of concurrency with PA 309;
signed as exit 60 eastbound
60.3097.0420B60B PA 145 north (South 4th Street)Westbound exit only
NorthamptonHellertown66.36106.802167 PA 412 – Hellertown, BethlehemAccess to Lehigh University and Sands Casino Resort Bethlehem
Lower Saucon Township71.04114.332271 PA 33 north to US 22 – StroudsburgSouthern terminus of PA 33; access to Pocono Mountains and Lehigh Valley Airport
Williams Township75.00120.702375 To PA 611 – Easton, PhiladelphiaAccess via Cedarville Road
Rest Area and Welcome Center (westbound only)
Delaware River Toll Plaza
(E-ZPass or cash, westbound only)
Delaware River77.10124.08Interstate 78 Toll Bridge
I-78 east – New York CityContinuation into New Jersey
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

See also[edit]


  1. ^ "Route Log - Main Routes of the Eisenhower National System Of Interstate and Defense Highways - Table 1". Federal Highway Administration. Retrieved 4 October 2014.
  2. ^
  3. ^
  4. ^ Steve Esack (2004-01-30). "Section of I-78 named to honor businessman Walter J. Dealtrey - Morning Call". Retrieved 2013-01-29.
  5. ^ 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.
  6. ^ "Interstate-Guide: Interstate 78". Retrieved March 26, 2016.
  7. ^ "Pennsylvania's Dearly Departed Interstates".
  8. ^ "I-178 (cancelled) Pennsylvania".
  9. ^ "1963 Rand McNally".
  10. ^ "I-178 Map".
  11. ^ Devlin, Ron (January 18, 2013). "PennDOT unveils upgrade to Interstate 78". Reading Eagle. Retrieved January 18, 2013.
  12. ^ Winfrey, Katiera; Wivell, Dawn (March 7, 2019). "PennDOT, Berks Planning Commission provide update on I-78". 69 News. Retrieved March 16, 2019.
  13. ^ Calculated using DeLorme Street Atlas USA 2007
  14. ^ a b "Pennsylvania Exit Numbering" (PDF). Pennsylvania Department of Transportation. Retrieved October 2, 2007.

External links[edit]

Route map:

KML is from Wikidata
Interstate 78
Previous state:
Pennsylvania Next state:
New Jersey