County routes in Suffolk County, New York, are maintained by the Suffolk County Department of Public Works and signed with the Manual on Uniform Traffic Control Devices-standard yellow-on-blue pentagon route marker. The designations do not follow any fixed pattern. Routes 76 to 100 are listed below.

County Route 76

County Route 76 is Town Line Road along the Islip–Smithtown township line. Until 1968, it was also part of Veterans Memorial Highway from Jericho Turnpike in Commack to Nesconset Highway in Hauppauge. The road shares a short concurrency with NY 111 in Hauppauge. An eastern extension to CR 16 was proposed at one time. The official Suffolk County Department of Public Works listing of county roads still includes this formerly proposed extension.

Major intersections

County Route 77

County Route 77 is the north-south road along the west side of Lake Montauk. It begins at an at-grade interchange of Montauk Point State Parkway as West Lake Drive where it intersects two streets that lead to the east side of Montauk Downs State Park, until it reaches CR 70. From here the road runs much closer to Lake Montauk, then intersects with other roads such as Star Island Road to the right, and then East Flamingo Road (former CR 95) to the left.

Before the road reaches the Block Island Sound, it intersects with the northern terminus of CR 49. The road then takes a sharp right turn along the sound then loops around in the opposite direction and passes by the ferry port to Block Island, before returning to the intersection with CR 49.

Major intersections The entire route is in Montauk.

County Route 77A

County Route 77A was the former east wye of CR 77 leading east towards Montauk Point State Parkway. Today it is CR 70.

County Route 77B

County Route 77B was the former west wye of CR 77 leading east towards Montauk Point State Parkway. Today it is part of CR 77.

County Route 78

County Route 78 is Church Street in the southeastern part of the town of Islip, from NY 27 to Division Avenue in Patchogue. Originally, it was also Veterans Memorial Highway from Nesconset to Sunrise highways until it was extended westward towards Jericho Turnpike in Commack in 1968, replacing part of CR 76. The southeast end of Veterans Memorial Highway bisected Church Street at Sunrise Highway, but only the part of Church Street on the south side of Sunrise Highway was a county road. The north side has never been anything else but a road maintained by the town of Islip. In 1972, Veterans Highway was acquired by the New York State Department of Transportation and designated NY 454, but Church Street remained CR 78.

Major intersections

County Route 79

County Route 79 is a north-south two-lane road, known as the Bridgehampton–Sag Harbor Turnpike.

History Known in pre-colonial times as the "Cart Path to Great Meadows," it was replaced by the Bull Head Turnpike Company as a private toll road, called the "Sag Harbor and Bull's Head Turnpike." Construction began in 1834 and the turnpike opened on March 29, 1837. The toll company shut down in 1905, and the toll houses were torn down in 1909.Tales from the Turnpike: Well-traveled byway is also a history mystery (Sag Harbor Express; January 22, 2009) The road was acquired by Suffolk County on November 10, 1948.

Major intersections

County Route 79A

County Route 79A was Main Street in Sag Harbor. It was established on October 23, 1952 and merged into CR 79 after the 1960s.

County Route 80

County Route 80 is the county route designation used for Montauk Highway (also labeled as Main Street, East Main Street and West Main Street) between East Patchogue and Shinnecock Hills.

County Route 80 Truck

Two Truck routes of County Route 80 exist in two locations. The first is in Moriches on Old Neck Road and Wilcox Avenue leading trucks around a low bridge beneath the Long Island Rail Road Montauk Branch. The second includes North Bay Avenue in Eastport, New York, which leads truck drivers from another low bridge for the same line within the community, then turns right overlapping Old Country Road into Speonk, where it turns south on North Phillips Avenue and ends at Montauk Highway just south of the Speonk (LIRR station). The latter of these was originally designated as New York State Route 27 Truck, when New York State Route 27 was part of Montauk Highway between Exits 61 and 65 on Sunrise Highway.

County Route 81

County Route 81 is the shortest county road in Suffolk County. Known as Wharf Street, the road consists entirely of a segment of the former Sag Harbor Branch of the Long Island Rail Road. It runs from an intersection with NY 114 (Bay Street) to the end of the pier on Gardiners Bay. The Sag Harbor Branch was abandoned in 1940, and the road was established in 1949. It is not signed.

County Route 82

County Route 82 is the designation for Higbie Lane from its starting point to Udall Road, and for most of Udall Road. It was named for the Richard Udall family who had an estate on South Country Road (now Montauk Highway). Higbie Lane starts as a two lane divided highway with a U-turn at NY 27A (Montauk Highway), between the historic La Grange Inn and the West Islip Public Library, and instantly becomes a two-lane undivided highway with a center-left-turn lane. Heading north, CR 82 intersect CR 50, immediately followed by an at-grade crossing of the Long Island Rail Road Montauk Branch near the Babylon Yard for the Babylon station, and then serves the west end of West Islip Boulevard, which runs along the north side of the tracks and becomes Orinoco Drive.

The route shifts to the northeast at a former wye onto Udall's Road, and Higbie Lane becomes a town of Islip maintained road. As Udall Road, CR 82 passes through another semi-residential area and then runs underneath the underpass of NY 27 between exits 40 and 41. The next moderate intersection is with Hunter Avenue and Muncey Road. Together these roads span from CR 34 to CR 57 between Sunrise Highway and the Southern State Parkway. CR 82 runs over the Southern State Parkway, but has no access to the parkway. The route finally ends at CR 57, however while CR 82 ends there, Udall Road continues as a town of Islip road towards Howell's Road, which leads to Corbin Avenue and eventually to the Deer Park station.

Major intersections The entire route is in West Islip.

County Route 83

County Route 83 is a major county road within the town of Brookhaven. It runs north and south from NY 27 (Sunrise Highway) at exit 52A in North Patchogue to NY 25A in Mount Sinai.

County Route 83A

County Route 83A was a formerly proposed spur that was intended to run from an unbuilt segment of CR 83 to Cedar Beach in Mount Sinai. It was supposed to run northwest, parallel to Pipe Stave Hollow Road, and end at Cedar Beach Town Park.

County Route 84

County Route 84 was a road that looped around northern Mattituck. This road included a bridge over Mattituck Creek that no longer exists. It began as Cox Neck Road on Sound Avenue, just west of the western terminus of what is today CR 48 (Middle Road). It had only one street even remotely resembling a major intersection, Bergen Avenue. The road takes a sharp right turn and heads east where it used to cross over Mattituck Creek. On the east side of Mattituck Creek, the road was Mill Neck Road. As Mill Neck Road became Oregon Avenue in Oregon, CR 84 turned south on Mill Road, where it crossed former CR 27A then CR 48 and headed back to NY 25 near East Mattituck.

County Route 85

County Route 85 is Montauk Highway between the Oakdale Merge and Patchogue.

County Route 86

County Route 86 runs from NY 25 and Dix Hills Road as Broadway–Greenlawn and Centerport Road into Little Neck Road in Centerport.

Route description CR 86 begins at the intersection of NY 25 and Dix Hills Road and at first runs northeast to southwest and immediately curves to a more northerly direction before the intersection of CR 35. Just northeast of Lekamb Avenue, the road straightens out, briefly moving direct north. This change is short-lived as it heads back northeast at Lantern Street. After passing two T-intersections connecting CR 86 to separate parts of Delamere Street, the road passes along the west side of a former apple grove that is now part of the Manor Plains Nature Park, a preserved land that is bisected by an L-shaped residential street which ends at Manor Road, a road which runs parallel to CR 86. Residences do turn up again on the east side north of the intersection with Leigh Street on the west side. Parkland turns up again on the same side just south of the opposite side of the intersection with Depew Street, only to end again at a local dog kennel. What passes for a major intersection at this point is Little Plains Road, which is also part of New York State Bicycle Route 25A.

The heart of Greenlawn is reached at the intersection of CR 9, the northwest corner of which contains Greenlawn Park, a local baseball field that runs along. The park is located along the west side of Broadway, east side of Cuba Hill Road, and south side of CR 11 (Pulaski Road), which it intersects almost instantly. Further into town, CR 86 passes an at-grade railroad crossing of the Port Jefferson Branch of the Long Island Rail Road close to Greenlawn Railroad Station. After passing the Harborfields Public Library, the road becomes much more residential. It curves to the left as it moves down the hills approaching the north shore, then makes a sharp curve to the northeast before the intersection with NY 25A at the Suydam Homestead.

History The road was once planned to be replaced by a four-lane divided highway known as CR 107, which would've extended it down towards Belmont Lake State Park and West Babylon.

Major intersections

County Route 87

County Route 87 is an unsigned county route on two-lane Edgewood Ave, which may have been part of NY 25A. The road runs southwest to northeast north of the Port Jefferson Branch of the Long Island Rail Road, and is inventoried as a west-to-east road.

Route description The road begins at the NY 25–NY 25A overlap in western Smithtown, at the north end of Brooksite Drive. Besides running north of the LIRR Port Jefferson Line, it also runs south of the Nissequogue River until it reaches Nissequogue River Road. Prior to this point, the road curves at a more easterly direction before the intersection of Landing Avenue. After passing by some surviving farmland as well as a middle school, the road enters the southernmost portion of the village of Head of the Harbor where it intersects Fifty Acre Road before ending at NY 25A in St. James.

Major intersections

County Route 88

County Route 88 is a two-lane highway known as Speonk–Riverhead Road, however the road doesn't go as far north as Riverhead as it originally did. The county describes the distance as being "3.8+ miles." The road terminates at the northeast corner of the Eastern Campus of Suffolk County Community College.

Route description CR 88 begins at CR 71 (Old Country Road) in Speonk, just east of Phillips Avenue, which serves as both a truck detour for County Route 80 (Suffolk County, New York), and as the road to Speonk's Long Island Railroad station. It was once planned to cross under the Port Jefferson–Westhampton Beach Highway.

Most of the road continues through a section of the Long Island Central Pine Barrens, which feature the indigenous dwarf pine. This area fell victim to a widespread wildfire that burned a significant portion of the core of the Pine Barrens in 1995. Halfway along its existence, the road serves as an overpass for NY 27, but does not have an interchange with it . After the road runs along the SCC Eastern Campus, CR 88 ends at CR 51 (East Moriches–Riverhead Road) in Northampton. The former section that actually got close to Riverhead is now only a dirt trail whose name only exists on paper.

Major intersections

County Route 89