The major exception to this is central and northern New Jersey, where it is a wide four-lane (or six-lane) divided strip, especially during much of its concurrency with US 1 and in Middlesex and Monmouth counties.

At New Gretna, US 9 exits the parkway and parallels wooded areas and marshlands along Little Egg Harbor and Manahawkin and Barnegat bays, passing Manahawkin and paralleling Long Beach Island, until South Toms River where the highway rejoins the Parkway for a third and final time through Toms River.

The concurrency, an important and busy regional artery, continues past Newark Liberty International Airport and over the Pulaski Skyway, finally leaving the state along with US 1 and I-95 via the George Washington Bridge.

At Fishkill, the road passes the historic Van Wyck Homestead Museum and it becomes a six-lane divided strip until reaching the Poughkeepsie city limit.

It is a busy surface road through the state capital, becoming a strip in its northern suburbs and taking traffic eventually to Saratoga Springs, Glens Falls and Lake George, at the edge of the Adirondack Park.

The Adirondack section of US 9 is the least trafficked of the road, returning to two lanes as it runs through vast tracts of forested wilderness and occasional hamlets.

It was rerouted to the west, via Sandman Boulevard and Lincoln Avenues, to meet the new ferry, and its southern stub into Cape May was renumbered as Route 109.

The official northern terminus (the point where the "End US 9" sign is posted) is just south of the interchange with I-87, less than a mile (1.6 km) from customs.