U.S. Route 1 (US 1) is a U.S. Route which parallels the East Coast of the United States, running from Key West, Florida, in the south to Fort Kent, Maine, at the Canadian border in the north. Of the entire length of the route, of it runs through New Jersey. It enters the state from Pennsylvania on the Trenton–Morrisville Toll Bridge over the Delaware River in the state capital of Trenton, running through the city on the Trenton Freeway. From here, US 1 continues northeast as a surface divided highway through suburban areas, heading into Middlesex County and passing through New Brunswick and Edison. US 1 merges with US 9 in Woodbridge, and the two routes continue through northern New Jersey as US 1/9 to the George Washington Bridge over the Hudson River in Fort Lee. At this point, the road continues into New York City along with I-95.
The current alignment of US 1 between Trenton and New Brunswick was chartered as the Trenton and New Brunswick Turnpike in 1803 and struggled throughout its 100-year existence. In 1913, the Lincoln Highway across the U.S. was created and connected Trenton to Newark within New Jersey. The Lincoln Highway was legislated as Route 13 between Trenton and New Brunswick in 1917 and as part of Route 1 between New Brunswick and Elizabeth, later extended to Jersey City. With the creation of the U.S. Highway System in 1926, US 1 was designated to follow the Lincoln Highway between Trenton and Newark and the current alignment of US 1/9 Truck to Jersey City, where it continued to the Holland Tunnel. In 1927, the Lincoln Highway portion of US 1 became Route 27. The current alignment of US 1 between Trenton and Newark was legislated as Route 26, Route S26, and Route 25, while the current route north from Jersey City to the George Washington Bridge became Route 1 and Route 6. In subsequent years, US 1 was moved onto its current routing between Trenton and the George Washington Bridge. The state highways running concurrent with US 1 were removed in 1953, around the same time the route was moved to the Trenton Freeway within Trenton and the old alignment became US 1 Alternate (US 1 Alt.), part of which is now US 1 Business (US 1 Bus.). By 1969, the Trenton Freeway was extended north to Whitehead Road in Lawrence Township, and that segment became Route 174. When the Trenton Freeway was completed north to US 1, the US 1 designation was shifted to the freeway, replacing Route 174.
Route description
Mercer County
US 1 crosses the Delaware River from Pennsylvania into New Jersey on the Trenton–Morrisville Toll Bridge, which is maintained by the Delaware River Joint Toll Bridge Commission. Once in Trenton, US 1 becomes the Trenton Freeway and is maintained by the New Jersey Department of Transportation (NJDOT). US 1 meets Route 29 at a partial diamond interchange just north of the river. As the road heads through the downtown area with Amtrak's Northeast Corridor railroad line running next to the route on the east side, it has a southbound exit and entrance with Warren Street that provides access to the New Jersey State House. It then comes to an interchange with the northern terminus of Route 129 as well as the western terminus of Route 33 near the Trenton Transit Center serving Amtrak, NJ Transit's Northeast Corridor and River lines, and SEPTA's Trenton Line.
At this point, the Trenton Freeway turns onto a depressed alignment, with Conrail Shared Assets Operations (CSAO)'s Enterprise Industrial Track railroad line closely parallel to the east, and comes to an interchange with Perry Street. The route turns northeast directly over the Delaware and Raritan Canal (D&R Canal), which still flows underneath, and has an exit for Olden Avenue. The freeway has a northbound ramp for Mulberry Street before the parallel railroad tracks curve east away from the road and there is a northbound exit and southbound entrance from the median that provides access to US 1 Bus. and US 206. Past this interchange, US 1 continues into Lawrence Township, where the surroundings become more wooded as the freeway has an exit for Whitehead Road. Along this stretch, the freeway closely parallels the canal, which emerges from under the freeway just north of Mulberry Street. The Trenton Freeway ends at the point US 1 Bus. merges back into US 1 at a southbound exit and northbound entrance.