New Jersey Route 21
 | ||||
| Route information | ||||
| Maintained by NJDOT | ||||
| Length | 14.35 mi[1] (23.09 km) | |||
| Existed | 1927–present | |||
| Major junctions | ||||
 I-78 in Newark NJ 27 in Newark I-280 in Newark NJ 7 in Belleville NJ 3 in Clifton | ||||
| Location | ||||
| Country | United States | |||
| State | New Jersey | |||
| Highway system | ||||
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Route 21 is a highway in northern New Jersey that stretches 14.35 miles from its southern terminus at an interchange with US 1-9 and US 22 in Newark to its northern terminus at an interchange with US 46 in Clifton.
The section of highway through Newark is known as the McCarter Highway. It parallels the elevated Pennsylvania Railroad tracks up to Newark Penn Station. The tracks are elevated on large stone constructions which (especially at night) present blind spots to drivers paralleling the tracks, resulting in frequent accidents. This portion was commissioned in 1934.
Between 1955 and 1959, the highway was extended northward as a freeway along the west bank of the Passaic River to an interchange with NJ 3. The road made it to the southern border between Clifton and Passaic by 1961. An extension to Paulison Avenue in Passaic opened in 1970, and a section to Monroe Street opened in 1974. For this last section, the river was rerouted, and the road clips Wallington in Bergen County without crossing today's river.
For a quarter-century, traffic headed for Paterson was dumped onto local streets in Passaic. Finally, in 1998, construction began on the "missing link" of the freeway, which opened December 22, 2000.
Sections of McCarter Highway are being improved as of 2006, where the road passes features such as Bears and Eagles Riverfront Stadium, the New Jersey Performing Arts Center, and the Newark Arena under construction for the New Jersey Devils. However, it is unlikely that this part of the road will ever become a freeway.
In April 2006, New Jersey Department of Transportation (NJDOT) replaced signs at the northern terminus of NJ 21.
History
Route 21 was first defined in the 1927 renumbering, and was extended north to Paterson in 1948. Since then, the route has been largely unchanged with the exception of upgrading much of the route to freeway standards, and an extension further north to its current terminus in Clifton.
When the freeway section between Chester Avenue in Newark and Route 7 in Belleville opened in 1960, the original alignment was for a time maintained as Route 21A, but it was decommissioned shortly thereafter.