Route 81 is a state highway in the U.S. state of New Jersey. The route is a freeway connector between exit 13A of the New Jersey Turnpike (Interstate 95) and U.S. Route 1/9 near Newark Liberty International Airport. It runs for 1.18 miles (1.90 km), entirely within the city of Elizabeth in Union County. A freeway called Route S100 was initially proposed on the current alignment of Route 81 in 1938; it, along with its parent Route 100, was never built. The current route was conceived in the 1960s as a freeway replacement for Route 164, which followed Humboldt Avenue, a surface road. It was to be designated Route 76, but was renumbered to Route 81 when Interstate 76 was created in New Jersey.