Interstate 78 in New Jersey

Interstate 78 in New Jersey is a major east–west highway spanning approximately 68 miles across the northern part of the state. It connects the Delaware River at the Pennsylvania border to the Holland Tunnel and New York City. The route serves critical transportation and economic roles, linking the Lehigh Valley with the New York metropolitan area and traversing diverse landscapes from rural Warren County to the dense urban core of Jersey City.

Route description

Beginning at the Delaware River crossing from Easton, Pennsylvania, the highway enters New Jersey at Phillipsburg. It proceeds east through the rolling hills of Hunterdon County, passing near Clinton and paralleling the South Branch Raritan River. The interstate then cuts through the Watchung Mountains via the Scotch Plains and continues across the suburban landscapes of Union County and Essex County. Its final segment is a complex elevated roadway through Jersey City, known as the Newark Bay Extension, which culminates at the approach to the Holland Tunnel. Key features along the corridor include the Phillipsburg toll bridge, the Garden State Parkway interchange, and the New Jersey Turnpike interchange in Newark.

History

The route's alignment was part of the original Interstate Highway System plans authorized by the Federal-Aid Highway Act of 1956. Construction began in the late 1950s, with the western sections opening first; the segment through Union County was completed by the mid-1960s. A major engineering challenge was the construction of the Newark Bay Extension, a elevated viaduct across Newark Bay and Hackensack River marshes, which opened in 1956 as part of the pre-Interstate system and was later incorporated into I-78. The final link, connecting to the Holland Tunnel, was completed in the 1980s after decades of planning and controversy in Jersey City. The highway's development spurred significant suburban growth in counties like Somerset and Hunterdon.

Exit list

The exit numbering sequence begins at the western terminus. Major exits include Exit 1 for US 22 in Phillipsburg, Exit 3 for Route 31 toward Clinton, Exit 7 for Route 173, and Exit 13 for Route 24 and I-287 near Springfield. In Union County, key interchanges are Exit 41 for the Garden State Parkway and Exit 48 for US 1/9 Truck. The easternmost exits, such as Exit 57 for the New Jersey Turnpike (I-95) in Newark and Exit 68 for Jersey Avenue in Jersey City, provide access to the Port Newark-Elizabeth Marine Terminal and Manhattan.

Major intersections

From west to east, I-78 intersects numerous significant highways. At its western terminus, it meets US 22. It crosses Route 31 and has a major junction with I-287 and Route 24. In Union County, it interchanges with the Garden State Parkway and US 22 again. Within Newark, it has a crucial confluence with the New Jersey Turnpike (I-95) and US 1/9. Its eastern terminus is a direct merge with the approach roads to the Holland Tunnel, which also carries NY 78, US 1/9, and US 46.

Auxiliary routes

There are no signed auxiliary Interstate highways (such as I-178 or I-278) directly branching from I-78 within New Jersey. However, the highway connects to several major auxiliary routes of the New Jersey Turnpike and other systems, including the Newark Bay Extension (historically designated as part of New Jersey Route 78), which functions as its final segment. The Interstate 78 corridor is also served by parallel and connecting routes like US 22, which provides an alternate arterial path through Union County and Essex County.

Category:Interstate 78 Category:Transportation in New Jersey