Interstate 78 is an Interstate Highway in the United States. It goes from Union Township, Lebanon County, Pennsylvania east to New York City. The route is 143.56 miles (231.04 km) long.
On the west, it starts at Interstate 81 northeast of Harrisburg, Pennsylvania. It passes through Allentown, Pennsylvania, and western and northern New Jersey. It goes in the Holland Tunnel to end in Lower Manhattan in New York City.
I-78 is a major road linking ports in the New York City and New Jersey area to points west. Over 4 million trucks use it annually. Trucks are 24% of all traffic. Truck traffic on the road is projected to rise once the widening of the Panama Canal is completed in 2015. With a wider canal, more Asian ships are expected to use East Coast ports.