Interstate 78 (I-78) is an east–west

Interstate Highway The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate Highway System, or the Eisenhower Interstate System, is a network of controlled-access highways that forms part of the National Hi ...

in the

Northeastern United States The Northeastern United States (also referred to as the Northeast, the East Coast, or the American Northeast) is List of regions of the United States, census regions United States Census Bureau. Located on the East Coast of the United States, ...

that runs from I-81 northeast of

Harrisburg, Pennsylvania Harrisburg ( ; ) is the capital city of the U.S. commonwealth of Pennsylvania and the seat of Dauphin County. With a population of 50,099 as of 2020, Harrisburg is the ninth-most populous city in Pennsylvania. It is the larger of the two pr ...

, through

Allentown Allentown may refer to: Places * Allentown, California, now called Toadtown, California * Allentown, Georgia, a city in four counties in Georgia * Allentown, Illinois, an unincorporated community in Tazewell County * Allentown, New Jersey, a boroug ...

to western and

North Jersey North Jersey, also known as Northern New Jersey, comprises the northern portions of the U.S. state of New Jersey between the upper Delaware River and the Atlantic Ocean. As a distinct toponym, North Jersey is a colloquial one rather than an a ...

, terminating at the

Holland Tunnel The Holland Tunnel is a vehicular tunnel under the Hudson River that connects Hudson Square and Lower Manhattan in New York City in the east to Jersey City, New Jersey, in the west. The tunnel is operated by the Port Authority of New York an ...

entrance to

Lower Manhattan Lower Manhattan, also known as Downtown Manhattan or Downtown New York City, is the southernmost part of the Boroughs of New York City, New York City borough of Manhattan. The neighborhood is History of New York City, the historical birthplace o ...

New York City New York, often called New York City (NYC), is the most populous city in the United States, located at the southern tip of New York State on one of the world's largest natural harbors. The city comprises five boroughs, each coextensive w ...

. Major metropolitan areas along I-78 include the

Lehigh Valley The Lehigh Valley () is a geography, geographic and urban area, metropolitan region formed by the Lehigh River in Lehigh County, Pennsylvania, Lehigh and Northampton County, Pennsylvania, Northampton counties in eastern Pennsylvania. It is a co ...

Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...

, the Gateway Region in New Jersey, and the

New York metropolitan area The New York metropolitan area, also called the Tri-State area and sometimes referred to as Greater New York, is the List of cities by GDP, largest metropolitan economy in the world, with a List of U.S. metropolitan areas by GDP, gross metropo ...

. I-78 links ports in New York City and

to points west, including the Lehigh Valley, the third-largest metropolitan region of

. I-78 accommodates over four million trucks annually, representing 24 percent of all truck traffic in the nation. It also is a major connection point to the New York metropolitan area's three major international airports,

Newark Liberty International Airport Newark Liberty International Airport is a major international airport serving the New York metropolitan area. The airport straddles the boundary between the cities of Newark, New Jersey, Newark in Essex County, New Jersey, Essex County and E ...

John F. Kennedy International Airport John F. Kennedy International Airport is a major international airport serving New York City and its metropolitan area. JFK Airport is located on the southwestern shore of Long Island, in Queens, New York City, bordering Jamaica Bay. It is ...

, and

LaGuardia Airport LaGuardia Airport ( ) – colloquially known as LaGuardia or simply LGA – is a civil airport in East Elmhurst, Queens, East Elmhurst, Queens, New York City, situated on the North Shore (Long Island), northwestern shore of Long Island, bord ...

Route description

, - , PA , , - , NJ , , - , , NY , , - , Total ,

Pennsylvania

I-78 begins at a directional T interchange with I-81 in Union Township, about northeast of

Harrisburg Harrisburg ( ; ) is the List of capitals in the United States, capital city of the Commonwealth (U.S. state), U.S. commonwealth of Pennsylvania and the county seat, seat of Dauphin County, Pennsylvania, Dauphin County. With a population of 50, ...

. Near the east end of the county, at exit 8, U.S. Route 22 (US 22) merges with I-78, and runs concurrently for the next through Berks and Lehigh counties. At exit 51, in Upper Macungie Township, US 22 leaves the highway. Drivers on I-78 eastbound must use this exit to access I-476, also known as the Northeast Extension of the

Pennsylvania Turnpike The Pennsylvania Turnpike, sometimes shortened to Penna Turnpike or PA Turnpike, is a controlled-access toll road which is operated by the Pennsylvania Turnpike Commission (PTC) in Pennsylvania. It runs for across the southern part of the st ...

, and westbound travelers must use exit 53 (northbound Pennsylvania Route 309, PA 309) and then westbound US 22. From exits 53 to 60, I-78 runs concurrently with PA 309. The six-lane overlap bypasses the city of

to the south and crosses South Mountain. At exit 60 (A–B going westbound), PA 309 yields south to Quakertown. Approximately east, there is an interchange between PA 412 and I-78 in Hellertown, serving

Bethlehem Bethlehem is a city in the West Bank, Palestine, located about south of Jerusalem, and the capital of the Bethlehem Governorate. It had a population of people, as of . The city's economy is strongly linked to Tourism in the State of Palesti ...

and

Lehigh University Lehigh University (LU), in Bethlehem, Pennsylvania, United States, is a private university, private research university. The university was established in 1865 by businessman Asa Packer. Lehigh University's undergraduate programs have been mixed ...

. At exit 71, PA 33 reaches its southern terminus at a

trumpet interchange In the field of road transport, an interchange (American English) or a grade-separated junction (British English) is a road junction that uses grade separations to allow for the movement of traffic between two or more roadways or highways, usi ...

. PA 33 traverses the

Pocono Mountains The Pocono Mountains, commonly referred to as the Poconos (), are a geographical, geological, and cultural region in Northeastern Pennsylvania. They overlook the Delaware River and Delaware Water Gap to the east, Lake Wallenpaupack to the nort ...

as it enters Bangor and crosses

I-80 Interstate 80 (I-80) is an east–west transcontinental freeway that crosses the United States from San Francisco, California, to Teaneck, New Jersey, in the New York metropolitan area. The highway was designated in 1956 as one of the ori ...

. The final exit on I-78 in Pennsylvania is Morgan Hill Road, which accesses PA 611 and Easton. I-78 then crosses the I-78 Toll Bridge and enters

New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...

New Jersey

After the I-78 Toll Bridge, I-78 enters New Jersey as the Phillipsburg–Newark Expressway. The road begins by running parallel with County Route 642 (CR 642) in the town of

Alpha Alpha (uppercase , lowercase ) is the first letter of the Greek alphabet. In the system of Greek numerals, it has a value of one. Alpha is derived from the Phoenician letter ''aleph'' , whose name comes from the West Semitic word for ' ...

. At , a

partial cloverleaf interchange A partial cloverleaf interchange or parclo is a modification of a cloverleaf interchange. The design has been well received, and has since become one of the most popular freeway-to-arterial interchange designs in North America. It has also bee ...

brings together US 22, Route 122, and Route 173 with I-78 in Phillipsburg. US 22 now runs concurrently with I-78 for the next . Going westbound, exit 4 leaves to the right for CR 637 and Warren Glen. The next exit, exit 6, is for CR 632 in

Bloomsbury Bloomsbury is a district in the West End of London, part of the London Borough of Camden in England. It is considered a fashionable residential area, and is the location of numerous cultural institution, cultural, intellectual, and educational ...

. The route number is not signed on I-78. Exit 7 in Bloomsbury is the first of several eastbound exits for Route 173, which runs parallel the Interstate. later, exit 11 leaves to the right as another exit for Route 173. CR 614 is located off the exit. Exit 12 westbound is for Route 173 again. Exit 12 eastbound is for a

frontage road A frontage road (also known as an access road, outer road, service road, feeder road, or parallel road) is a local road running parallel to a higher-speed, limited-access road. Where parallel high-speed roads are provided as part of a maj ...

paralleling I-78. Exit 13 is only westbound and is another exit for Route 173. Nearby the exit, going eastbound, the frontage road merges in. Exit 15 is for Route 173 and CR 513 in Franklin Township. Exit 17 is for Route 31 in Clinton Township. In Annandale, US 22 leaves I-78 at exit 18. US 22 continues to Bound Brook and Union County. At exit 20, CR 639 intersects. CR 639 heads to the Round Valley Reservoir. Exit 24 is for CR 523 to Oldwick. At exit 29, I-287, US 202, and US 206 interchange with I-78 in Bedminster. At this point, in Somerset County, exits 33, 36, and 40 are for county routes in Warren Township. At exit 41, I-78 enters Union County and then passes through the Watchung Reservation, where land bridges cross over the highway to allow for the safe passage of wildlife. At exit 45, CR 527 intersects after paralleling for some time. West of exit 48, I-78 splits into express and local highways. Exit 48 is for Route 24 in Springfield Township. Exit 49A is for one of Route 24's spur routes, Route 124. Exit 52 is for the

Garden State Parkway The Garden State Parkway (GSP) is a Controlled-access highway, controlled-access toll road that stretches the north–south length of eastern New Jersey from the state's southernmost tip near Cape May, New Jersey, Cape May north to the New York ...

in Union Township. At exits 57 and 58, Route 21, US 1, US 9, and US 22 intersect I-78. The exit provides access to

. East of exit 58 at the eastern tip of Newark, I-78 becomes the Newark Bay Extension of the

New Jersey Turnpike The New Jersey Turnpike (NJTP) is a system of controlled-access highway, controlled-access toll roads in the U.S. state of New Jersey. The turnpike is maintained by the New Jersey Turnpike Authority (NJTA).The Garden State Parkway, although ma ...

. Past the first toll plaza, I-78 has an interchange with

I-95 Interstate 95 (I-95) is the main north–south Interstate Highway on the East Coast of the United States, running from U.S. Route 1 (US 1) in Miami, Florida, north to the Houlton–Woodstock Border Crossing between Maine and the ...

(New Jersey Turnpike) and crosses

Newark Bay Newark Bay is a tidal bay at the confluence of the Passaic and Hackensack Rivers in northeastern New Jersey. It is home to the Port Newark-Elizabeth Marine Terminal, the largest container shipping facility in Port of New York and New Jerse ...

via the Newark Bay Bridge. The first exit, 14A, is for Route 440 in

Bayonne Bayonne () is a city in southwestern France near the France–Spain border, Spanish border. It is a communes of France, commune and one of two subprefectures in France, subprefectures in the Pyrénées-Atlantiques departments of France, departm ...

Liberty State Park Liberty State Park (LSP) is a park in the U.S. state of New Jersey, located on Upper New York Bay in Jersey City, New Jersey, Jersey City opposite Liberty Island and Ellis Island. The park opened in 1976 to coincide with United States Bicenten ...

can be reached by taking exit 14B. Exit 14C is the final numbered exit, providing access to the

Liberty Science Center Liberty Science Center is an interactive science museum and learning center located in Liberty State Park in Jersey City, New Jersey, Jersey City, New Jersey, United States. At its opening, it was the largest such planetarium in the Western H ...

. Route 139 runs concurrently with I-78 along a

one-way pair A one-way pair, one-way couple, or couplet refers to that portion of a bi-directional traffic facilitysuch as a road, bus, streetcar, or light rail linewhere its opposing flows exist as two independent and roughly parallel facilities. Descriptio ...

of surface streets as it approaches the

and enters

New York New York most commonly refers to: * New York (state), a state in the northeastern United States * New York City, the most populous city in the United States, located in the state of New York New York may also refer to: Places United Kingdom * ...

state.

New York

I-78's length in

is —half of the Holland Tunnel and the egress-only

roundabout A roundabout, a rotary and a traffic circle are types of circular intersection or junction in which road traffic is permitted to flow in one direction around a central island, and priority is typically given to traffic already in the junct ...

immediately beyond the end of the tunnel. The route was planned to run east and north through New York City to end at

the Bronx The Bronx ( ) is the northernmost of the five Boroughs of New York City, boroughs of New York City, coextensive with Bronx County, in the U.S. state of New York (state), New York. It shares a land border with Westchester County, New York, West ...

, but sections of the planned route, including the Lower Manhattan Expressway, were canceled. In New York City, I-78 continues through the egress-only roundabout known as the Saint John's Rotary. The five separate exits from the Rotary are assigned numbers, exits 1 to 5, in counterclockwise order. Exit 5, the last eastbound exit, leads onto Canal Street. Under original plans, I-78 was to cross

Manhattan Manhattan ( ) is the most densely populated and geographically smallest of the Boroughs of New York City, five boroughs of New York City. Coextensive with New York County, Manhattan is the County statistics of the United States#Smallest, larg ...

as the Lower Manhattan Expressway onto the Williamsburg Bridge and then beyond I-278 on Bushwick Expressway through

Brooklyn Brooklyn is a Boroughs of New York City, borough of New York City located at the westernmost end of Long Island in the New York (state), State of New York. Formerly an independent city, the borough is coextensive with Kings County, one of twelv ...

into

Queens Queens is the largest by area of the Boroughs of New York City, five boroughs of New York City, coextensive with Queens County, in the U.S. state of New York (state), New York. Located near the western end of Long Island, it is bordered by the ...

near the

. A section of I-78 at the airport was built as the Nassau Expressway, later I-878 and now

New York State Route 878 New York State Route 878 (NY 878) is an limited-access road, expressway on Long Island in New York (state), New York state. The route exists in two sections, which both form the Nassau Expressway. NY 878's western terminus is th ...

(NY 878), though most of the westbound side was never built. Under the plans, east of the airport, I-78 would have turned north on the Clearview Expressway, built north of Hillside Avenue in Queens and now I-295, run across the

Throgs Neck Bridge The Throgs Neck Bridge is a suspension bridge in New York City, carrying six lanes of Interstate 295 (New York), Interstate 295 (I-295) over the East River where it meets the Long Island Sound. The bridge connects the Throggs Neck section of t ...

, and forked into two spurs, ending at I-95 via the Throgs Neck Expressway, which is now I-695 and the Bruckner Interchange via the

Cross Bronx Expressway The Cross Bronx Expressway is a major controlled-access highway, freeway in the New York City borough of the Bronx. It is mainly designated as part of Interstate 95 in New York, Interstate 95 (I-95), but also includes portions of Interstate ...

, which is now part of I-295.

Junction list

;Pennsylvania : west-northwest of

Jonestown The Peoples Temple Agricultural Project, better known by its informal name "Jonestown", was a remote settlement in Guyana established by the Peoples Temple, an American religious movement under the leadership of Jim Jones. Jonestown became in ...

: east-northeast of Fredericksburg. The highways travel concurrently to east-northeast of Fogelsville. : west of

: southwest of Easton ;New Jersey : east-northeast of

. The highways travel concurrently to Annandale. : in Bedminster : in Springfield : in Union Township : in Newark : in Newark ;New York : Canal Street in

Auxiliary routes

All of I-78's auxiliary routes serve New York City; however, none of these routes actually intersect I-78, following the route's truncation at the eastern end of the

. * runs from US 1/9 in

Linden, New Jersey Linden is a City (New Jersey), city in southeastern Union County, New Jersey, Union County, in the U.S. state of New Jersey. It is part of the New York metropolitan area, located about southwest of Manhattan and bordering Staten Island, a boro ...

, over the Goethals Bridge, through

Staten Island Staten Island ( ) is the southernmost of the boroughs of New York City, five boroughs of New York City, coextensive with Richmond County and situated at the southernmost point of New York (state), New York. The borough is separated from the ad ...

, over the Verrazzano-Narrows Bridge and through

and

, and across the

Triborough Bridge The Robert F. Kennedy Bridge (RFK Bridge; also known by its previous name, the Triborough Bridge) is a complex of bridges and elevated expressway viaducts in New York City. The bridges link the boroughs of Manhattan, Queens, and the Bronx. Th ...

into

to end at

at the Bruckner Interchange. I-278 was planned to extend west from

Elizabeth, New Jersey Elizabeth is a City (New Jersey), city in and the county seat of Union County, New Jersey, Union County, in the U.S. state of New Jersey.Springfield Township, Union County, New Jersey Springfield Township is a township in Union County, in the U.S. state of New Jersey. The township is located on a ridge in northern- central New Jersey, within the Raritan Valley and Rahway Valley regions in the New York metropolitan area ...

, and was to intersect I-78 at the east end of the Williamsburg Bridge in Brooklyn. Until 1972, I-278 ran along present- NY 895 and a proposed extension to I-95, while I-278 east of NY 895 was I-878. * is an unsigned designation for the

Brooklyn–Battery Tunnel The Hugh L. Carey Tunnel, commonly referred to as the Brooklyn–Battery Tunnel, Battery Tunnel or Battery Park Tunnel, is a toll road, tolled tunnel in New York City that connects Red Hook, Brooklyn, Red Hook in Brooklyn with The Battery (Ma ...

, a spur from I-278 into

. Plans were made to continue it north along the

West Side Highway The Joe DiMaggio Highway, commonly called the West Side Highway and formerly the Miller Highway, is a mostly surface section of New York State Route 9A (NY 9A), running from 72nd Street (Manhattan), West 72nd Street along the Hudso ...

( NY 9A) to I-78 at the Holland Tunnel, though the project was later canceled. * runs from I-278 at the Bruckner Interchange south over the Bronx–Whitestone Bridge to

. It was to intersect I-78 at its south end. Original plans took I-678 west on the

Grand Central Parkway The Grand Central Parkway (GCP) is a 14.61-mile (23.51 km) controlled-access parkway that stretches from the Triborough Bridge in New York City to the Queens– Nassau County line on Long Island. At the Nassau County line, it becomes t ...

to I-278. * is an unsigned designation for part of NY 878, a short west–east freeway on the north edge of John F. Kennedy International Airport. It was once planned as part of I-78 and now intersects I-678. The number was assigned in 1970. *A former I-878 existed from 1959 to 1972 along present I-278 east of NY 895. (NY 895 was part of I-278.) In the

region of eastern Pennsylvania, PA 378, which exits in downtown

was once I-378 but was predesignated as a state route after I-78 was rerouted to a new southerly alignment. I-178 was initially planned to extend in

Center City Allentown Center City Allentown is the downtown and central business district of Allentown, Pennsylvania, the third-largest city in the U.S. state of Pennsylvania. It has a dense population and is currently undergoing an urban revitalization process. ...

, but local opposition to the plan led to it being cancelled.