Interstate 278 (I-278) is an auxiliary Interstate Highway in New Jersey and New York in the United States. The road runs 35.62 miles (57.32 km) from US Route 1/9 (US 1/9) in Linden, New Jersey, northeast to the Bruckner Interchange in the New York City borough of the Bronx. The majority of I-278 is in New York City, where it serves as a partial beltway and passes through all five of the city's boroughs. I-278 follows several freeways, including the Union Freeway in Union County, New Jersey; the Staten Island Expressway (SIE) across Staten Island; the Gowanus Expressway in southern Brooklyn; the Brooklyn–Queens Expressway (BQE) across northern Brooklyn and Queens; a small part of the Grand Central Parkway in Queens; and a part of the Bruckner Expressway in the Bronx. I-278 also crosses multiple bridges, including the Goethals, Verrazzano-Narrows, Kosciuszko, and Robert F. Kennedy bridges.

U.S. Route 1/9 is the 31.01-mile (49.91 km) long concurrency of US 1 and US 9 from their junction in Woodbridge Township in Middlesex County, New Jersey, north to New York City. The route is a multilane road with some freeway portions that runs through urbanized areas of North Jersey adjacent to New York City. Throughout most of its length in New Jersey, the road runs near the New Jersey Turnpike/Interstate 95 (I-95). In Fort Lee, US 1/9 merges onto I-95 and crosses the Hudson River on the George Washington Bridge, where the two U.S. Routes split a short distance into New York. US 1/9 intersects several major roads, including I-278 in Linden, Route 81 in Elizabeth, I-78 and US 22 in Newark, Route 139 in Jersey City, Route 3 and Route 495 in North Bergen, and US 46 in Palisades Park. US 1/9 also serves as the primary access point to Newark Airport. Between Newark and Jersey City, US 1/9 runs along the Pulaski Skyway. Trucks are banned from this section of road and must use US 1/9 Truck. The concurrency between US 1 and US 9 is commonly referred to as "1 and 9". Some signage for the concurrency, as well as the truck route, combines the two roads into one shield, separated by a hyphen (1-9) or an ampersand (1&9).