Before 1916 What is now US 46 west of Netcong was part of the Manunkachunk Trail, an old Lenape trail running from the Great Minisink Trail in Netcong west to Manunkachunk Village, now Belvidere. Another Lenape trail extended from Netcong to what is now Parsippany and
Springfield Township. In 1809, the
Parsippany and Rockaway Turnpike was chartered to extend from the
Newark-Pompton Turnpike to the Union Turnpike; the section east from Denville was later named Bloomfield Avenue. A branch of the Union Turnpike was chartered in 1813 to run west from Dover to the Morris Turnpike; it was locally known as the
Dover Turnpike. By 1920, the portion of the modern route west of Hackettstown was signed as an easterly extension of the
Lackawanna Trail, running through
Pennsylvania to
Binghamton, New York. This designation was removed by 1924, when the state of Pennsylvania rerouted the highway south to
Philadelphia.
Routes 5, 10 and 12: 1916–1927 Prior to 1927, what is today US 46 was followed by three different routes. The first route was pre-1927 Route 5, which was first legislated in 1916. It began by crossing the Delaware River from Pennsylvania at the community of Delaware. Several undercrossings of the
Delaware, Lackawanna and Western Railroad near Delaware were bypassed with a short new road on the southwest side of the railroad. From there, Route 5 used the existing Delaware Road to north of Belvidere, then the Buttzville-Belvidere Road to
Buttzville, the Buttzville Road to
Great Meadows, and the Danville Mountain Road to Hackettstown. From Hackettstown to Denville, Route 5 ran concurrently with pre-1927 Route 12, which was first legislated in 1917. A mostly-new road (now eastbound US 46) was built from Hackettstown east to Netcong to avoid steep
grades on the existing roads. Portions of the existing Budd's Lake Road were used between Budd Lake and Netcong. From Netcong the route used the old
Morris Turnpike to Ledgewood and the
Dover Turnpike to Dover, running into Dover on Blackwell Street. Blackwell Street led to Rockaway Road, becoming Main Street in Rockaway, from which it used the old
Parsippany and Rockaway Turnpike to Denville. In the
1927 renumbering, Route 6 was assigned to the route across northern New Jersey, using the old Route 5 from Delaware to Netcong, Route 12 from Hackettstown to Paterson, and a generally new alignment parallel to Route 10 from Paterson to the proposed George Washington Bridge; the old Route 10 alignment between Paterson and Edgewater was to become
Route 5. In Paterson, Route 6 was marked along McBride Avenue, Spruce Street and Market Street. Route 6 was redefined in 1929 to use none of the old road east of Paterson (it had formerly been planned to use Market Street west of roughly where
Route 17 now crosses it), and Route 5 was cut back to run only east from
Ridgefield. The portion of pre-1927 Route 10 that was bypassed by Route 6 was designated
Route 10N, but was eventually removed from the state highway system. In addition, Route 6 was redefined to bypass Paterson to the south. The new route would enter Paterson just south of Market Street, but then turn south and southwest before heading back west to rejoin the old route at the east end of the Little Falls bypass at the Union Boulevard crossing. The old road along Union Boulevard towards Paterson was assigned
Route S6, as a spur of Route 6. In December 1937, a section of highway was opened from the Passaic River at
Clifton to
Hasbrouck Heights, marking the completion of Route 6 with the exception of the Paterson bypass. In 1938, a spur of Route 6 called
Route 6A was legislated to run from Route 6 in Dover north to US 206/
Route S31 in
Lafayette Township; this became Route 15 in 1953. A realignment at the Passaic River crossing near Pine Brook was built in the 1940s, along with a new road for a short distance west from Pine Brook. Also in the 1940s, the road was widened west into Denville, and a bypass of downtown Denville, including an
interchange at
Route 5N (now Route 53) was built.
U.S. Route 46: 1936–present In 1925, the US 46 designation was first proposed for a route in
Colorado connecting
Grand Junction to
Limon, but it instead became
US 40S. The current US 46 was marked in 1936 between
Portland, Pennsylvania, and the George Washington Bridge. At the time, the new Route 6 had not been completed from
Route 2 (now
Route 17) west to
Route S6 (now
Route 62), and so US 46 was marked through Paterson until this portion was completed by the 1940s. Following this, US 611 was rerouted to cross the river twice in order to use the freeway through the
Delaware Water Gap, and US 46 was moved to former Route 94 (pre-1953
Route 8) to end at the Columbia, New Jersey side of the Portland-Columbia Toll Bridge. The former approaches to the Darlington's Bridge, which itself was dismantled by the
Delaware River Joint Toll Bridge Commission in 1954, became
Route 163 in New Jersey and State Route 1039 in Pennsylvania. The US 611 freeway was designated I-80 by 1960, and US 611 was moved back to its old all-Pennsylvania alignment in 1965, leaving US 46 to end at I-80 and Route 94. In 1964, the approach to the George Washington Bridge, shared with US 1-9, was rebuilt into a freeway that became a part of I-95. Since then, many changes have occurred to US 46. A traffic circle served the intersection with Route 23 until the construction of I-80, and a
spaghetti interchange was constructed to replace it. The Little Ferry Circle, initially constructed in 1933, was modified in 1985 to allow US 46 to run straight through the circle. In 1998, the Ledgewood Circle at the western terminus of Route 10 was replaced with a signalized T-intersection. In 2007, the NJDOT announced that they would eliminate the Little Ferry Circle by turning it into a straight intersection; work ran through 2014. In addition, the interchange between US 46 and the western terminus of Route 3 is planned to be reconstructed. This project will reconfigure ramps, bring bridges up to standard, and will provide for three-lane connections between Route 3 and US 46. It was announced in 2003 and is projected to cost over $250 million. Construction on the first contract began in December 2015 with completion by October 2019. Construction on the second contract began in February 2020. The Little Ferry Circle was reconstructed in 1985, creating a through road to let Route 46 traffic pass through the circle without causing congestion. In 1988 the Legislature resolved that "The Commissioner of Transportation shall designate that portion of United States Highway Route 46 located between Hope Road and Barkers Mill Road in the township of Independence, Warren County as 'Clifford Jones Avenue'," honoring
United States Army Specialist Clifford Jones, Jr., a resident of Independence Township who had been killed in action in 1968 during the
Vietnam War. The Little Ferry Circle was widened in 1998; this involved condemnation of adjacent properties and led to a 73-page court decision. In March 2007, the
New Jersey Department of Transportation proposed its latest plan to address issues at the circle. The plan would realign the circle into a straight intersection, complete with turning lanes; prohibit left turns onto many residential streets; and would include construction of a pump station to move water off the oft-flooded highway and into the Hackensack River. The proprietors at the site also claim to have lost a significant amount of business due to reduced accessibility to their establishments, caused by the redesign and loss of the former circle. ==Major intersections==