A road originally known as the Washington Turnpike ran from Phillipsburg to Morristown, via Washington (in Warren County), Long Valley, and Chester. From there, the Morris and Essex Turnpike continued on to Springfield and Newark, with a spur heading toward Elizabeth on the same straight line as the road between Chatham and Springfield. These roads together were legislated in 1927 as NJ 24, but at least some of them were part of the state highway system even before 1927. Abutments on certain highway bridges on NJ 57 read “STATE HIGHWAY ROUTE 12”, reflecting the highway’s prior number.
NJ 24 had two spurs on it. One of them ran from Stephensburg (in Mansfield Township, Warren County) to Hackettstown, as an extension that paralleled the Musconetcong River. (The original turnpike crossed the river at Stephensburg and climbed one side of Schooley’s Mountain before coming down to Long Valley.) The other, the Morris Turnpike leg from Springfield to Elizabeth, is now NJ 82. The Schooley’s Mountain section of the Washington Turnpike was never taken over as a state highway (or, perhaps, even a county road – it is municipally maintained today). However, the state did take over Mountain Avenue in Hackettstown, which runs from the end of what had become NJ S-24 to Route 46; that is NJ 182 today. Meanwhile, all of Schooley’s Mountain Road, all of which was maintained by Morris County, eventually became signed as NJ 24 to form the missing connection between the two sections of state-maintained 24.
Eventually, NJ 24 from Phillipsburg to Stephensburg and NJ S-24 from Stephensburg to Hackettstown were redesignated as NJ 57, the number that had originally been given to Mountain Avenue in Hackettstown. This indicated that the state had abandoned the idea of linking the two sections of 24. However, it is only in the last few years that signs indicating that the Morris section of the old turnpike were NJ 24 have slowly come down. Chester Township calls its section of the old turnpike “Old Route 24” now. Meanwhile, the “Morris & Essex” name of 24 east of Morristown has migrated westward, over the old Washington Turnpike, now NJ 57.
| Mile | Street Name | Feature | ||
| 21.10 | Eastern terminus of , Hackettstown Town, Warren Co |
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| 21.10 | |
  Mountain Ave |
 |
Schooleys Mountain Rd |
| 20.54 | |
Hackettstown Town, Warren Co Mansfield Twp, Warren Co |
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| 20.54 | |
Trout Brook | bridge | Trout Brook |
| 20.52 | |
Shopping center entrance | |
|
| 20.12 | |
Allen Rd | |
Newburg Rd |
| 19.79 | |
Shopping center entrance | |
|
| 19.35 | |
Airport Rd | |
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| 18.13 | |
Hances Brook | bridge | Hances Brook |
| 17.80 | |
Branch Musconetcong River | bridge | Branch Musconetcong River |
| 15.80 | |
 Watters Rd |
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| 15.46 | |
Unnamed stream | bridge | Unnamed stream |
| 14.39 | Morris & Essex Tpk |  Port Murray Rd |
|
Point Mountain Rd |
| 14.09 | Morris & Essex Tpk | Anderson Rd |
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| 13.91 | Morris & Essex Tpk | Unnamed stream | bridge | Unnamed stream |
| 12.67 | Morris & Essex Tpk | Mansfield Twp, Warren Co Washington Twp, Warren Co |
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| 12.13 | Morris & Essex Tpk | McCullough Rd |
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| 12.11 | Morris & Essex Tpk | Washburn Rd |
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| 12.07 | Morris & Essex Tpk | Lackawanna Railroad | overpass | Lackawanna Railroad |
| 11.60 | |
Washington Twp, Warren Co Washington Boro, Warren Co |
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| 11.13 | Washington Ave | Lackawanna Railroad | underpass | Lackawanna Railroad |
| 11.12 | Washington Ave | Unnamed stream | bridge | Unnamed stream |
| 11.01 | Washington Ave |  |
|
|
| 10.76 | Washington Ave | Belvidere Ave | |
Broad St |
| 10.65 | Washington Ave | Lincoln Ave | |
Lincoln Ave |
| 10.32 | Washington Ave | Prospect St | |
Prospect St |
| 10.15 | Washington Ave | Shabbecong Creek | bridge | Shabbecong Creek |
| 9.79 | |
Washington Boro, Warren Co Washington Twp, Warren Co |
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| 9.73 | Morris & Essex Tpk |  Brass Castle Rd |
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| 9.55 | Morris & Essex Tpk | Pohatcong Creek | bridge | Pohatcong Creek |
| 8.81 | Morris & Essex Tpk | Brass Castle Creek | bridge | Brass Castle Creek |
| 8.51 | Morris & Essex Tpk |  Little Philadelphia Rd |
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| 8.27 | Morris & Essex Tpk | Washington Twp, Warren Co Franklin Twp, Warren Co |
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| 7.59 | Morris & Essex Tpk | Unnamed stream | bridge | Unnamed stream |
| 6.53 | Morris & Essex Tpk | Mill Brook Rd | |
Asbury-Broadway Rd |
| 6.43 | Morris & Essex Tpk | Mill Brook | bridge | Mill Brook |
| 5.82 | Morris & Essex Tpk | Branch Pohatcong Creek | culvert | Branch Pohatcong Creek |
| 5.22 | Morris & Essex Tpk | Branch Pohatcong Creek | culvert | Branch Pohatcong Creek |
| 5.03 | Morris & Essex Tpk | Edison Rd |
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| 4.55 | Morris & Essex Tpk | Unnamed stream | bridge | Unnamed stream |
| 3.58 | Morris & Essex Tpk | Franklin Twp, Warren Co Greenwich Twp, Warren Co |
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| 2.65 | Morris & Essex Tpk | Merrill Creek | bridge | Merrill Creek |
| 2.19 | Morris & Essex Tpk |  Liberty Rd |
|
North Main St |
| 2.07 | Morris & Essex Tpk | Greenwich Twp, Warren Co Lopatcong Twp, Warren Co |
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| 1.53 | Morris & Essex Tpk | Lopatcong Creek | bridge | Lopatcong Creek |
| 1.52 | Morris & Essex Tpk |  Uniontown Rd |
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Uniontown Rd |
| 0.56 | Morris & Essex Tpk | Strykers Rd | |
Strykers Rd |
| 0.07 | Morris & Essex Tpk | underpass |  west |
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| 0.00 | Morris & Essex Tpk | |
merge | |
| 0.00 | Western terminus of , Lopatcong Twp, Warren Co |
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| Road continues westward as Morris & Essex Tpk |
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