Interstate 78

Interstate 78 Pennsylvania


Interstate 78 originates in a rural area east of Harrisburg, Pennsylvania and ends at the Holland Tunnel linking Jersey City, New Jersey with Manhattan, New York. The freeway provides a trucking corridor to North Jersey from Central Pennsylvania in lieu of the tolled Pennsylvania and New Jersey Turnpikes. Through the Allentown, Bethlehem and Easton area, the freeway acts as a bypass along South Mountain and Morgan Hill to Alpha, New Jersey.

East from the Delaware River, Interstate 78 intertwines with New Jersey Route 173 (the former alignment of U.S. 22) across Musconetcong Mountain to the Spruce Run Reservoir area and Clinton. U.S. 22 emerges along an route independent of I-78 east from Lebanon to Newark while I-78 stays north to Berkeley Heights, New Providence and Summit. The two routes converge east from Union and Irvington at the interchange complex with New Jersey Route 21, U.S. 1/9 by Newark Liberty International Airport (EWR).

Beyond the freeway along U.S. 1/9 leading north to Pulaski Skyway and I-95 (New Jersey Turnpike), Interstate 78 shifts onto the tolled New Jersey Turnpike Extension across Newark Bay to Jersey City. The limited access route ends at the one way couplet of 12th and 14th Streets between Jersey Avenue and the Holland Tunnel west portal. This stretch travels at-grade through four signalized intersections.

The Holland Tunnel carries motorists below the Hudson River to the area of Hudson Square and Soho in Manhattan, New York. Eastbound I-78 emerges at a loop encircling St. John’s Park with five ramps departing in succession to the adjacent street grid between Hudson and Varick Streets. The westbound beginning includes ramps from Canal Street, Watts Street and Varick Street two to three blocks to the north.

High Priority Corridor

Interstate 78 in New Jersey is part of High Priority Corridor 63: Liberty Corridor.

Parallel U.S. Routes

Interstate 78 parallels or directly replaced U.S. 22 from near Harrisburg, Pennsylvania east to Newark, New Jersey. The New Jersey Turnpike Extension loops to the south opposite U.S. 1/9 along the Pulaski Skyway.


Origins of I-78 predate the Interstate system with a 1950 upgrade of U.S. 22 to an expressway from the Lebanon County line to Exit 13 (PA 501). The four lane roadway extended east from PA 501 at Bethel to Exit 17 (PA 419) in 1951. Work continued with construction of the Lehigh Valley Thruway from Allentown to the Delaware River commencing in 1952. The Thruway was finished in 1955, as was the portion between PA 419 and Exit 19 (PA 183 by Strausstown). When the Interstate system was established in 1958, two additional sections of U.S. 22 freeway were completed: Exits 23 to 30 (Hamburg) and from Exit 30 to the Lehigh County line.1

All of Interstate 78 west of the Lehigh Valley Thruway was completed in 1970.1 Resistance from residents of Phillipsburg, New Jersey in 1968 halted work on the connection from the Lehigh Valley Thruway to Interstate 78 east of Alpha. This led to the eventual realignment of I-78 to the south of Allentown, Bethlehem and Easton. Work on the new I-78 broke ground in 19841, with completion on November 21, 1989.2

Through New Jersey, Interstate 78 was completed in August 1986 when the controversial section through Watchung Reservation was finally opened to traffic.3 The New Jersey Turnpike Extension was constructed between 1954 and September 1956. The Holland Tunnel opened to traffic on November 13, 1927. It consists of a 8,371 foot long tube for eastbound and a 8,558 foot tube for westbound.4

The planned eastern extent of Interstate 78 through New York City included the following routes east and north to Interstate 95 in the Bronx:

  • Lower Manhattan Expressway (unconstructed) – from the Holland Tunnel east to the Williamsburg Bridge
  • Williamsburg Bridge (opened in 1903) – east to the Bushwick Expressway
  • Bushwick Expressway (unconstructed) – east to the Nassau Expressway at Southern Parkway
  • Nassau Expressway (completed eastbound in 1971, westbound unbuilt) – east to the Clearview Expressway
  • Clearview Expressway (completed from NY 25 northward in 1963) – north to the Throgs Neck Bridge
  • Throgs Neck Bridge – (opened in 1961) north to a split with Cross Bronx Expressway (I-78 mainline and Throgs Neck Expressway (I-78 Spur).

I-78 was deleted through New York City between Interstate 278 (Brooklyn-Queens Expressway) and the planned junction of the unconstructed Bushwick Expressway at the Nassau Expressway by the American Association of State Highway and Transportation Officials (AASHTO) on June 23, 1969. The same action redesignated I-78 along the short Nassau Expressway as Interstate 878 and I-78 along the Clearview Expressway north from Hillside Avenue as Interstate 295.

Route Information

  • East End – Manhattan, NY

  • West End – Lickdale, PA

  • Branch Routes – 4

  • Total Mileage – 146.28

Pennsylvania – 77.95

  • Cities – Allentown, Bethlehem, Easton

  • JunctionsI-81 I-476 PA Turnpike

New Jersey – 67.83

  • Cities – Plainfield, Irvington, Newark, Jersey City

  • JunctionsI-287 I-95

New York – 0.50

  • Cities – New York City

  • Junctions – none

Source: December 31, 2021 Interstate Route Log and Finders List

I-78 Annual Average Daily Traffic (AADT)

Location Vehicles per day
Bethel Twp, PA 33,000
Allentown, PA 95,000
Bethlehem, PA 65,000
Holland Tunnel, NY 84,194

Source: Pennsylvania Traffic Volume Map 2017 (Penndot)
2016 AADT NYSDOT Traffic Data Viewer

New York City - 1961
New York City – 1961

The majority of the proposed sections of Interstate 78 shown on this map in 1961 were never built. This includes the route southeast from the Williamsburg Bridge to Southern Parkway and the Clearview Expressway north to Hillside Avenue.

Portions of Conduit Boulevard were also expanded to accommodate the eastern most stretch of the Bushwick Expressway. A large grassy median remains in place from the canceled freeway.

U.S. 22 Interstate Proposal

In Section 1602 of TEA-21 (1998), Item 14 appropriated $100,000 to the study of including U.S. 22 between U.S. 250 and/or Interstate 77 in Ohio and Pittsburgh, Pennsylvania, within the Interstate Highway System. In July 1998, a group of highway officials from Ohio, Pennsylvania, and West Virginia met to discuss this issue. Their claim was that this upgrade would boost the area’s economy. Nothing further arose from this specific proposal since then, although sections of U.S. 22 constitute freeway standards through central Pennsylvania.

East End – NY 9A East End of Holland Tunnel – Manhattan, New York City, New York

I-78 East

I-78 east at Jersey Av - Jersey City, NJ

Combining with traffic from Route 139, Interstate 78 lowers to grade level at Jersey Avenue in Jersey City. Unsigned at this point, the ensuing three blocks of I-78 follow the couplet of 12th Street east and 14th Street west between the New Jersey Turnpike Extension and the Holland Tunnel. 05/30/22

I-78/12th St east at Marin Blvd - Jersey City, NJ

I-78/12th Street intersects Marin Boulevard at the fourth and final traffic light preceding the Holland Tunnel toll collection point. 05/30/22

I-78 east at Holland Tunnel

Interstate 78 east descends into Holland Tunnel beyond Marin Boulevard and the site of the former main line toll plaza. 08/09/04

I-78 east at Holland Tunnel

The Holland Tunnel accommodates just two lanes per direction. Passing is prohibited. 05/30/22

I-78 east at NY 9A - Manhattan

Interstate 78 emerges from the Holland Tunnel alongside Canal Street in lower Manhattan. The roadway curves south ahead of turn offs for NY 9A (West Street) via Laight Street and Hudson Street north at Beach Street. 05/30/22

I-78 east at NY 9A - Manhattan

Two lanes continue beyond the departure of Exit 1 for NY 9A (West Street). 05/30/22

I-78 east at Hudson St - Manhattan, NY

Exit 2 follows from I-78 east for Beach Street west and Hudson Street north to Uptown. 05/30/22

I-78 east at Beach St - Manhattan, NY

Exit 3 connects with Beach Street east toward the Manhattan Bridge to Brooklyn and Varick Street south to Downtown. 05/30/22

I-78 east at Varick St - Manhattan, NY

Completing a 360 degree turn, the eastbound roadway for I-78 partitions with two lanes turning onto Varick Street south at Exit 4. 05/30/22

I-78 east at Laight St - Manhattan, NY

Two lanes from the end of I-78 at Exit 5 cross Varick Street onto the continuation of Laight Street east to Canal Street at 6th Avenue. 05/30/22

Varick Street – North at I-78 Holland Tunnel

Hudson St north at Vestry St - Manhattan, NY

Northbound Hudson Street connects with the Holland Tunnel west at Canal Street, one block beyond Vestry Street. Photo by Dan Moraseski (Winter 2001).

Varick Street – South at I-78 Holland Tunnel

Varick St south at Spring St / I-78 - Manhattan, NY

Varick Street heads two blocks south from Spring Street to the entrance for the Holland Tunnel taking Interstate 78 west from Manhattan to Jersey City, New Jersey. 05/30/22

Canal Street – North at I-78 Holland Tunnel

Canal St west at Hudson St / I-78 - Manhattan, NY

Canal Street angles northwest through Lower Manhattan from the Manhattan Bridge and Chinatown to the Holland Tunnel entrance at Hudson Street. 05/30/22

NY 9A South at I-78 Holland Tunnel

NY 9A south at I-78/Holland Tunnel - Manhattan
NY 9A/West St south at I-78 - Manhattan

NY 9A (West Street) proceeds a quarter mile south from Clarkson Street to intersect Canal Street (Exit 3). Canal Street angles southeast four blocks to one of the entrance ramps for the Holland Tunnel. 08/09/04

Canal St south at I-78/Holland Tunnel - Manhattan, NY

Heading southeast from Canal Park, Canal Street heads three blocks to Hudson Street and the entrance ramp for Interstate 78 west though the Holland Tunnel. Photo by Chris Mason (07/21/02).

Canal St south at I-78/Holland Tunnel - Manhattan, NY

Dual left turn lanes connect Canal Street south with Interstate 78 to Jersey City, New Jersey just after Watts Street. Photo by Chris Mason (07/21/02).

Holland Tunnel entrance at Broome St - Manhattan, NY

Ramps from Canal Street and Hudson Street north combine with ramps from Varick Street south and Watts Street west ahead of the portal into the Holland Tunnel. I-78 passes below the Hudson River with two westbound lanes. Photo by Cesar Centano (08/22/08).

West End I-81 – near Lickdale, Pennsylvania

I-78 West at I-81

I-78 west at I-81 - Union Twp, PA

Two miles ahead of the directional T interchange with Interstate 81 on I-78 west ahead of Swatara Creek. Photo by Mark Moore (06/17/16).

I-78 west at I-81 - Union Twp, PA

The mainline of Interstate 78 west defaults onto I-81 south ahead of Indiantown Gap Military Reservation. I-81 leads west 18.1 miles to split with Interstate 83 south near Colonial Park. Photo by Mark Moore (06/17/16).

I-78 west at I-81 - Union Twp, PA

Exit 1A leads motorists northward along I-81 through Swatara Gap of Blue Mountain to Hazelton. I-81 connects Harrisburg with Wilkes-Barre and Scranton along a 232 mile course through PA. Photo by Mark Moore (06/17/16).

I-81 South at I-78

I-81 south at I-78 - Union Twp, PA

Leading away from Fisher Avenue and Lickdale, I-81 south passes through an industrial park area on the 0.75 mile approach to Interstate 78 (Exit 89). Photo by Mark Moore (06/18/16).

I-81 south at I-78 - Union Twp, PA

Interstate 81 south overtakes the ending westbound lanes of I-78 and advances 23 miles to the capital city of Harrisburg. Photo by Mark Moore (06/18/16).

I-81 South at I-78

I-81 north at I-78 - Union Twp, PA

The first sign for Interstate 78 east posted along I-81 north references Reading. Reading lies south of the I-78 corridor via PA 61 (old U.S. 122) from Hamburg, midway to Allentown. Photo by Mark Moore (06/18/16).

I-81 north at I-78 - Union Twp, PA

Interstate 81 runs east-west between the Harrisburg area and the split with I-78. The freeway passes just south of Fort Indiantown Gap military reservation on the two mile approach to I-78 (Exit 89). Photo by Mark Moore (06/18/16).

I-81 north at I-78 - Union Twp, PA

One mile ahead of the directional T interchange (Exit 89) with Interstate 78 east on I-81 north. I-81 continues 56 miles to the city of Hazelton and 62 miles to the junction with Interstate 80. Photo by Mark Moore (06/18/16).

I-81 north at I-78 - Union Twp, PA

Long distance truckers are advised to remain along Interstate 81 north to I-84 east at Scranton to bypass the New York City metropolitan area. I-78 and I-80 both lead I-81 motorists directly to the Big Apple otherwise. Photo by Mark Moore (06/18/16).

I-81 north at I-78 - Union Twp, PA

Interstate 81 north makes a nearly 90 degree turn at Exit 89 for the approach to Swatara Gap across Blue Mountain. Interstate 78 continues the eastern trajectory, overtaking U.S. 22 east of Fredericksburg, en route Allentown. Photo by Mark Moore (06/18/16).

I-81 north at I-78 - Union Twp, PA

Interstate 81 continues northeast with two lanes toward Hazelton and Wilkes-Barre while two lanes depart at Exit 89 for Interstate 78 east. U.S. 22 combines with I-78 between Exits 8 and 51 outside Allentown. Photo by Mark Moore (06/18/16).

I-78 East

I-78 east at I-81 - Union Twp, PA

The first confirming marker for Interstate 78 east stands within the exchange at I-81. The freeway proceeds 5.8 miles east to PA 343 near Fredericksburg. Photo by Dan Moraseski (09/02/02).

I-78 West End Throwback

I-81 north at I-78 - 2002

A new sign bridge replaced this assembly at the I-78 east and 81 northbound split by 2007. Photo by Jonathan Lebowitz (12/27/02).

I-78 west at I-81 - 1994

Former button copy overheads at the ramp split for I-81 on I-78 west. 19 miles separate I-78 from the northern end of I-83 near Colonial Park. 01/94

I-81 south at I-78 - 1994

Illuminated overheads previously posted at the unnumbered exit for I-78 east from I-81 south. This sign bridge was eventually replaced. 01/94

I-81 north at I-78 - 1994

Replaced button copy overheads at the I-78/81 split. Prior to the Pennsylvania’s systemwide exit renumbering in 2001, many of the Interstate junctions were unnumbered. 01/94