Route 124 is a state highway in the northern part of New Jersey in the United States that is long. It is the eastern section of what used to be Route 24 before that road was realigned to its current freeway alignment. The western end is at an intersection with U.S. Route 202 (US 202) and County Route 510 (CR 510) in Morristown, Morris County; the eastern end continues as CR 603 on Springfield Avenue at the border between Maplewood and Irvington in Essex County. The route runs through suburban areas of Morris County, passing through Madison and Chatham. It intersects Route 24 on the border of Millburn, Essex County and Summit, Union County, and serves as a frontage road for that route. Upon splitting from Route 24, Route 124 continues east through Springfield Township, Union Township, and Maplewood to its eastern terminus.
The alignment of today's Route 124 was first designated as a part of pre-1927 Route 5 in 1916, a route that was to run from Delaware, Warren County, to Newark. In 1927, this portion of the route became a part of Route 24, a route that was to run from Phillipsburg to Newark. A freeway, which is the current alignment of Route 24, was proposed for this portion of the route in the 1950s that was approved in 1960. Route 24 was moved to the new freeway between the John F. Kennedy Parkway on the Millburn/Summit border and Interstate 78 (I-78) in 1972, with Route 124 being designated along the former alignment of Route 24 east of this point. In 1992, the Route 24 freeway was completed between I-287 in Hanover Township and the John F. Kennedy Parkway. As a result, Route 124 was extended west along the former Route 24 to US 202 in Morristown.
Route description
Morris County
thumb|left|Westbound Route 124 at CR 607 in Chatham
Route 124 begins at the intersection of US 202 and CR 510 at the Park Place square in the downtown of Morristown, Morris County. From here, it heads to the southeast as South Street, a two-lane undivided road that passes businesses. At the intersection with CR 663, the road widens to four lanes. In a short distance, Route 124 intersects CR 608, at which point the route has an eastbound ramp to eastbound Route 24 and a westbound ramp from westbound Route 24. before being designated as a part of pre-1927 Route 5, a route that was legislated in 1916 to run from Delaware, Warren County, east to Newark. In the 1927 New Jersey state highway renumbering, this portion of pre-1927 Route 5 became a part of Route 24, a road that was to run from Phillipsburg to Newark. In the 1950s, plans were made to bypass this portion of Route 24 with a freeway running from I-287 in Hanover Township to I-78 in Springfield Township; this was approved of in 1960. This freeway was completed between I-78 and the John F. Kennedy Parkway in 1972. The Route 24 designation was moved to the new freeway and Route 124 was designated along the former alignment of Route 24 east of this point, which included frontage roads built where the new freeway ran along the old alignment of the road. Following the completion of the Route 24 freeway to I-287 in 1992, Route 124 was extended west along the former alignment of Route 24 between the John F. Kennedy Parkway and US 202 in Morristown. In 2002, maintenance of the portion of Route 124 in Maplewood was transferred to the municipality from the New Jersey Department of Transportation (NJDOT).