Interstate 78 in New York

Interstate 78 (I-78) is a part of the Interstate Highway System that runs from Union Township, Lebanon County, Pennsylvania, to New York City. In the US state of New York, I-78 extends 0.5 miles (0.80 km). The entirety of I-78 consists of the Holland Tunnel, which crosses under the Hudson River from New Jersey and ends at an exit rotary in Lower Manhattan. The tunnel and its approaches are maintained by the Port Authority of New York and New Jersey (PANYNJ).

I-78 was planned to take a longer route when the Interstate System within New York City was originally proposed in the late 1950s. The proposed route of I-78 was to head east via the Williamsburg Bridge to John F. Kennedy International Airport and then north over the Throgs Neck Bridge to I-95 in the Bronx. One unbuilt section of I-78, the Lower Manhattan Expressway, would have connected the Holland Tunnel to the Williamsburg and Manhattan Bridges. Another unbuilt section, the Cross-Brooklyn and Bushwick Expressways, would have extended southeast across Brooklyn, connecting to what is now the Nassau Expressway (New York State Route 878 or NY 878). A third section would have connected the Nassau Expressway, at the southern edge of Queens near JFK Airport, to the southern end of what is now I-295, in central Queens. Due to opposition from the communities along the expressways' routes, these sections of I-78 were never built, and I-78 does not connect to I-278 or to any of its other auxiliary routes.