U.S. Route 9 (US 9) is a United States Numbered Highway in the Mid-Atlantic region of the United States, running from Laurel, Delaware, to Champlain, New York. In New Jersey, the route runs from the Cape May–Lewes Ferry terminal in North Cape May, Cape May County, where the ferry carries US 9 across the Delaware Bay to Lewes, Delaware, north to the George Washington Bridge in Fort Lee, Bergen County, where the route along with Interstate 95 (I-95) and US 1 continue into New York City. US 9 is the longest U.S. Highway in the state.

From North Cape May north to Toms River in Ocean County, US 9 is mostly a two-lane undivided road that closely parallels the Garden State Parkway (GSP) and runs near the Jersey Shore. Along this stretch, it passes through the communities of Rio Grande, Cape May Court House, Somers Point, Pleasantville, Absecon, Tuckerton, Manahawkin, Beachwood, and Berkeley Township. In Toms River, US 9 runs along the GSP for a short distance before heading northwest away from it and the Jersey Shore into Lakewood Township.

Upon entering Monmouth County, the route grows to a multilane suburban divided highway, as it continues through Howell Township, Freehold Township, Manalapan Township, Marlboro Township, Old Bridge Township, Sayreville, and South Amboy. This section of the route is an important commuter artery from these bedroom communities into North Jersey and New York City, and helps New York and North Jersey residents reach popular destinations such as the Freehold Raceway, Freehold Raceway Mall, and the Jersey Shore. In Woodbridge Township, US 9 merges with US 1 and the two routes run concurrently through northern New Jersey as US 1/9 to the George Washington Bridge, where they continue into New York.

Before 1927, the current alignment of US 9 had been legislated as parts of several New Jersey state highways, including the original Route 14 from Cape May to Seaville, Route 19 between Seaville and Absecon, the original Route 4 between Absecon and Lakewood and South Amboy and Rahway, Route 7 Spur between Lakewood and Freehold, and the original Route 1 between Rahway and Jersey City. US 9 was initially only signed through New Jersey in 1926 to run from US 30 in Absecon north to the New York border in Alpine, where it became US 9W; it ran more to the east of its current alignment between Lakewood and South Amboy. In 1927, US 9 became Route 4 between Absecon and Lakewood and South Amboy and Rahway, Route 35 between Lakewood and Belmar and Eatontown and South Amboy (now Route 88 south of Point Pleasant), Route 4N (now Route 71) between Belmar and Eatontown, Route 27 between Rahway and Newark, Route 25 between Newark and Jersey City, and Route 1 north of Jersey City.

By the 1940s, US 9 had been extended south on Route 4 to Cape May and rerouted to current Route 4 between Lakewood and South Amboy. In addition, the route was moved to its current alignment between South Amboy and Jersey City, following Route 35 and Route 25, and routed to cross the Hudson River on the George Washington Bridge, using a part of Route 6. The state highway concurrencies were removed in 1953, and two realignments occurred to the route as a result of the construction of the GSP in the 1950s. Once the GSP was opened in 1954, its traffic temporarily concurred to the Beasley's Point bridge. This concurrency would be removed in 1955, with the completion of the Little Egg Harbor Bridge. In the 1970s, US 9 was extended across the Cape May–Lewes Ferry to continue into Delaware with the former route into Cape May becoming Route 109. Also around this time, two freeways were proposed for US 9 in Atlantic and Monmouth counties but never built. The Beesley's Point Bridge over Great Egg Harbor Bay was closed in 2004, with US 9 rerouted to use the Great Egg Harbor Bridge along the GSP in 2013.

Route description Cape May County From the Cape May Terminal off of the Cape May–Lewes Ferry toll plaza, which carries US 9 across the Delaware Bay to Lewes, Delaware, US 9 continues north on Ferry Road, a divided highway with one northbound lane and three southbound lanes which is under the maintenance of the Delaware River and Bay Authority. The road soon turns east and becomes four-lane divided Lincoln Boulevard. It runs between the residential community of North Cape May to the north and wetlands to the south within Lower Township, Cape May County. The road becomes Sandman Boulevard at the intersection with County Route 603 (CR 603), where it enters woodland and narrows into a two-lane undivided road. After a turn southeast, US 9 comes to a crossroads with CR 626, which heads south to cross the Cape May Canal as Route 162. After crossing the Cape May Seashore Lines railroad tracks, US 9 turns north onto Shore Road, while Route 109 continues straight to head south into Cape May. Shore Road, which is maintained by the New Jersey Department of Transportation (NJDOT), carries the route northward through a mix of woods and marshland containing some development, with the Cape May Seashore Lines tracks running immediately to the west and the GSP a short distance to the east. The road passes near Historic Cold Spring Village prior to a brief bend farther to the east of the railroad tracks as the route continues west of the Cape May National Golf Club and through Erma.

US 9 crosses into Middle Township, where it continues northeast into the commercial community of Rio Grande. Here, the road briefly widens to four lanes as it has an intersection with Route 47, which runs up the west bank of the cape. From this point, the two-lane route continues into a mix of woods and development. Heading into Burleigh, US 9 intersects Route 147 and CR 618. Route 147/CR 618, as well as Route 47, provide access to the Wildwoods resort area on the Jersey Shore. North of the Route 147 intersection, US 9 draws alongside the GSP as it passes near The Shore Club golf course. Shortly after pulling away from the GSP once again, the highway continues into Cape May Court House, the county seat of Cape May County.

In this community, US 9 runs past a mix of homes and businesses, intersecting CR 674 and CR 657, both of which provide access to the GSP at their respective interchanges. At the CR 657 intersection, US 9 briefly gains a center left-turn lane and passes west of Cape Regional Medical Center. Upon leaving Cape May Court House, the route runs into more rural surroundings and comes to an intersection with CR 609, which heads east to an interchange with the GSP, and Zoo Road, which heads west to the Cape May County Park & Zoo. Past here, the road again draws closer to the parkway and comes to a ramp that provides access to the southbound direction of the parkway. Continuing northeast through more wooded development, US 9 intersects CR 601 before entering Dennis Township.

A short distance later, in the community of Clermont, Route 83 splits off to the northwest. Past this intersection, US 9 continues northeast through more rural areas, reaching an intersection with CR 625 after passing by Magnolia Lake. Following the CR 625 intersection, the road comes to CR 550, which heads to the west. Not long after the CR 550 intersection, US 9 continues into Upper Township, where it passes rural development before reaching Seaville. Here, there is an intersection with the southern terminus of Route 50 and a ramp providing access to the southbound direction of the GSP and from the northbound direction of the GSP. At this intersection, the route is briefly a divided highway. Past this junction, the road continues northeast, where residential development becomes more constant alongside the road as it passes through Palermo.

US 9 reaches the community of Marmora, where it heads into commercial areas and briefly becomes a divided highway as it intersects CR 623. At this intersection, US 9 turns southeast to run concurrent with CR 623 on Roosevelt Boulevard, while Shore Road continues north into Beesley's Point to a dead end at the site of the former Beesley's Point Bridge; this section of Shore Road is still inventoried as part of US 9 by NJDOT even though it no longer carries through traffic along US 9 since the bridge was closed and demolished. US 9/CR 623 then runs southeast as five-lane road with a center left-turn lane that passes businesses. The road comes to an interchange with the GSP, with a park-and-ride lot located within the northwest quadrant of the interchange. At this interchange, US 9 heads northeast on the four-lane limited-access tolled parkway while CR 623 continues to Ocean City. The parkway, which has a wide median, carries the route through wooded areas between Beesley's Point to the west and marshland to the east. The median narrows as the highway comes to the Great Egg Harbor Bridge over the Great Egg Harbor Bay.

Atlantic County

The highway then crosses the Great Egg Harbor Bay into Egg Harbor Township, Atlantic County, where it runs across marshy Drag Island into Somers Point before passing over the Drag Channel. Southbound drivers of both US 9 and the GSP are then required to pay a toll at the Little Egg toll plaza before US 9 leaves the roadway at a partial interchange. Now called New Road, the route runs through developed areas prior to crossing CR 559. The road winds east through the Greate Bay Golf Club, before turning north and intersecting the northern terminus of Route 52, a route leading to Ocean City, and West Laurel Drive, which provides access to the northbound GSP and from the southbound GSP. At this intersection, the road contains a median. From this point, the two-lane undivided US 9 is lined with businesses and continues northeast, gaining a center left-turn lane prior to the CR 559 Alternate (CR 559 Alt.) intersection. Here, the route enters Linwood and the turn lane ends as it heads through suburban areas. The road continues into Northfield, where it comes to CR 563. US 9 enters Pleasantville, intersecting US 40/US 322 (Black Horse Pike), a surface route to nearby Atlantic City to the east. The road turns more north-northeast past this intersection, crossing a trail and the Southern Railroad of New Jersey's Pleasantville Industrial Track line. The route reaches an interchange with the Atlantic City Expressway, the toll road leading into Atlantic City.

After this interchange, US 9 crosses CR 646 and enters Absecon. The route crosses the marshy Absecon Creek prior to passing businesses. After crossing under NJ Transit's Atlantic City Line, another route into Atlantic City, US 30 (White Horse Pike), intersects with US 9. After US 30, the route turns east into wooded neighborhoods, becoming Wyoming Avenue. Route 157 then intersects US 9 from the south, with US 9 making a left turn to head northeast onto Shore Road. The road continues into Galloway Township, with residential development becoming less dense as it runs a short distance to the west of inland bays, intersecting with the southern terminus of CR 561.

Past this intersection, US 9 draws farther from the inland bays and becomes New York Road. The road continues through dense woodland with some housing where it then reaches Smithville. Here, it intersects with the southern terminus of CR 561 Bypass before it crosses CR 561 Alt. Upon leaving Smithville, the land it crosses gets much more dense with trees. The road turns slightly north-northwest as it crosses the marshy Nacote Creek, entering Port Republic and continuing north. After intersecting with CR 575, the road passes a dedicated monument for the Battle of Chestnut Neck as it intersects the southern terminus of the southern segment of Route 167. Following this intersection, US 9 turns west and merges onto the GSP at an interchange. The limited-access parkway, which is six lanes wide, carries US 9 north through marshland to a crossing of the Mullica River. Despite the GSP being a toll road, there are no tolls to pay through this segment.

Pine Barrens