Interstate 78 (
I-78) is an east–west route stretching from
Union Township, Lebanon County, Pennsylvania to
New York City. In
New Jersey, I-78 is called the
Phillipsburg–Newark Expressway and the
Newark Bay Extension of the
New Jersey Turnpike. The highway runs for in the northern part of the state of New Jersey from the
Interstate 78 Toll Bridge over the
Delaware River at the
Pennsylvania state line in
Phillipsburg,
Warren County east to the
Holland Tunnel under the
Hudson River at the
New York state line in
Jersey City,
Hudson County. The Phillipsburg-Newark Expressway portion of I-78, formally called the
Lightning Division Memorial Highway, runs from the Phillipsburg area east across rural areas of western New Jersey before entering suburban areas in
Somerset County. The road crosses the
Watchung Mountains, widening into a
local-express lane configuration at
Route 24 as it continues through urban areas to
Newark. Here, I-78 intersects the mainline of the New Jersey Turnpike (
I-95) and becomes the Newark Bay Extension, crossing the
Newark Bay Bridge and continuing to Jersey City. The route, along with
Route 139, follows a
one-way pair of surface streets to the Holland Tunnel.