County Route 516 (CR 516) is a county highway in the U.S. state of New Jersey.

The highway extends 19.2 miles (30.9 km) from Route 18/CR 527 in Old Bridge to Route 36 in Middletown. It is known as Old Bridge-Matawan Road for its entire length in Old Bridge where it interchanges with US 9, and then continues several more miles to the Old Bridge/Matawan border, where it enters Monmouth County. There it is known as New Brunswick Avenue and forms part of the boundary between Matawan and Aberdeen before fully entering Matawan. Upon crossing the intersection with Main Street (Route 79) it becomes known as Broad Street and continues past Route 34 to another intersection of Main Street (CR 516 Spur). From there it follows Main Street north into Aberdeen where it is known as Lower Main Street; the name changes again upon entering Keyport where it becomes Maple Place.

In Keyport, CR 516 has a grade-separated interchange with Route 35; part of this 1965 alignment follows West 4th Street before rejoining Maple Place and following it to Green Grove Avenue. Turning east on Green Grove Avenue, CR 516 bridges Chingarora Creek and enters Hazlet where it is known as Middle Road, which intersects with Route 36 and continues into Holmdel to the intersection of Laurel Avenue. It turns briefly south on Laurel Avenue, then has its second intersection of Route 35. Running concurrently with Route 35 into Middletown, CR 516 then turns off onto Cherry Tree Farm Road and continues along that alignment to Leonardville Road, which it follows to its eastern terminus at the intersection of Route 36 in Middletown.

A segment of Main Street in Downtown Matawan – one block west of Broad Street (mainline CR 516) – is maintained by the county as a segment of CR 516 Spur. On most county-maintained traffic signals along Main Street, it is signed as CR 516 though the signal at Little Street signs the road as "CR 516S." The street extends 0.9 miles (1.4 km) from the intersection of Route 79 and Route 34 to the intersection of Main and Broad streets.

Another 0.3-mile-long (0.48 km) spur consists of Green Grove Avenue between Maple Place and 1st Street (CR 6). Though heading west from Route 35 shows CR 516 making a left onto Maple Place, one CR 516 reassurance shield (without a "Spur" plaque) appears at Green Grove Avenue's intersection with 1st Street.

West of Matawan, the road was maintained by the Middlesex and Monmouth Turnpike Company.

Before the county route system, the road from Keyport to Atlantic Highlands was part of the Jersey Coast Way, which ran from the Staten Island Ferry to Cape May. CR 516 was established in 1952 as a part of the 500 Series system. It incorporated part of Middlesex County Route 3-R-14 between Old Bridge and the Monmouth County line. From Old Bridge to its junction with Route 4 (now Route 79), CR 516 was concurrent with Route S28, although always a county road. In 1953, Route S28 was renumbered as Route 18; the concurrency ended when Route 18 was realigned to the south. From the Monmouth County line it absorbed part of CR 6 through Matawan and Aberdeen to Keyport. There it superseded CR 42 in its entirety. CR 42 consisted of Maple Place in Keyport between Route 35 and Green Grove Avenue. CR 42 was taken over as a county highway by resolution of the Board of Chosen Freeholders on June 21, 1939. Since 1952, no route in Monmouth County has been designated as CR 42. From CR 42, it continued east from Keyport east through Hazlet, Holmdel and Middletown townships. It used a part of CR 7 to its terminus.

CR 516 Alternate was previously the designation of Broad Street in Matawan, but was never signed differently than the parent route. Initially both Main and Broad streets were designated as CR 516. Broad Street was then briefly renumbered as CR 516 Alternate, with Main Street remaining as the main stem. When CR 516 was rerouted from Main Street to Broad Street, and Main Street renumbered as CR 516 Spur, CR 516 Alternate ceased to exist.

County	Location	mi	km	Destinations	Notes
Middlesex	Old Bridge Township	0.0– 0.0	0.0– 0.0	Route 18 / CR 527 south to N.J. Turnpike – Englishtown, Freehold, New Brunswick	Western terminus; interchange, access to Route 18 northbound and from Route 18 southbound; west end of the overlap with CR 527
		0.3	0.48	CR 527 north (Old Matawan Rd)	East end of the overlap with CR 527
		3.1	5.0	US 9 – The Amboys, Freehold	Interchange
Monmouth	Matawan	6.9	11.1	Route 79 (Main St) to G.S. Parkway
		7.1	11.4	Route 34 – The Amboys, Point Pleasant
	Keyport	9.2	14.8	Route 35 – The Amboys, Red Bank	Interchange
	Hazlet	10.7	17.2	Route 36 to G.S. Parkway – Highlands, The Amboys
	Holmdel Township	13.8	22.2	Route 35 north – Keyport, South Amboy	West end of the overlap with Route 35
	Middletown Township	14.3	23.0	Route 35 south – Red Bank	East end of the overlap with Route 35
		19.2	30.9	Route 36 south	Eastern terminus; access to Route 36 south / from Route 36 north only
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus       Incomplete access

• U.S. Roads portal
• New Jersey portal

• Resolution, June 21, 1939, Monmouth County Board of Chosen Freeholders
• 1940 Road Map of Monmouth County, Monmouth County Board of Chosen Freeholders
• 1952 Road Map of Monmouth County, Monmouth County Board of Chosen Freeholders

• NJ State Highways: CR 515-530