| Caption: | Former standard route marker for county routes in Suffolk County; CR 13A shield on CR 50 in Bay Shore. |
| Interstate: | Interstate X (I-X) |
| Us: | U.S. Route X (US X) |
| Statehwy: | New York State Route X (NY X) |
| Label1: | County: |
| Field1: | County Route X (CR X) |
| Links: | NY |
| County: | Suffolk |
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 1 to 25 are listed below.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 1 |
| Length Mi: | 1.52 |
| Length Round: | 2 |
| Length Ref: | [1] |
| Location: | Amityville–North Amityville |
| Formed: | 1930[2] |
County Route 1 is known as County Line Road and extends for 1.52miles through the town of Babylon. It begins at NY 27A (Montauk Highway) in Amityville and heads north to the intersection of Joyce Avenue in East Farmingdale. Parts of the road enter Nassau County; however, the Nassau County sections are not part of CR 1.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 2 |
| Length Mi: | 8.53 |
| Length Round: | 2 |
| Length Ref: | [3] |
| Location: | Amityville–Dix Hills |
| Formed: | 1930 |
County Route 2 is mostly known as Straight Path and extends from the village of Amityville to the town of Huntington. It begins at an intersection with NY 110 in Amityville and heads east along Dixon Avenue to CR 47 in Copiague. From there it begins to move to the northeast until it eventually becomes Straight Path before the intersection with NY 27 in North Lindenhurst. The road widens into a four-lane divided highway ahead of its junction with CR 3 (Wellwood Avenue). This intersection contains turning ramps on all corners except the southwest corner, where Heathcote Road ends. The divider ends at Sherbrooke Road and the North Lindenhurst Fire Department, where the road returns to a four-lane undivided highway.
The road intersects an at-grade crossing with the Central Branch of the Long Island Rail Road. From there the road crosses NY 109 and meets the Southern State Parkway. As CR 2 approaches the interchange with the parkway, the road becomes narrower despite remaining four lanes wide. On the northwest corner of this interchange is the beginning of St. Johns Catholic Cemetery, where the road widens to accommodate a center left-turn lane. The northern border of the cemetery is along Edison Avenue, located near the intersection with Little East Neck Road in Wyandanch.
CR 2 narrows to two lanes with stretches occasionally featuring medians. North of Commonwealth Drive, the road become four lanes with no left-turn lane until it approaches the vicinity of Wyandanch Station. Past Winter Avenue, CR 2 narrows back down to two lanes, but with a center left-turn lane. The road continues in this manner until it reaches its terminus at an intersection with NY 231 in Half Hollow Hills.
CR 2 was assigned on January 27, 1930, to the portion of its alignment between Albany Avenue in Amityville and modern NY 231 in Huntington. It was extended west along Dixon Avenue to NY 110 on February 5, 1943, replacing CR 2A. An extension beyond NY 231 was proposed during the 1960s and 1970s and officially added to CR 2's alignment on June 22, 1961. The terminus was to be at the Long Island Motor Parkway; however, this extension was never built. The intersection between CR 2 and NY 27 was once intended to be upgraded into an interchange.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 2A |
| Location: | Amityville–North Lindenhurst |
| Header Type: | former |
County Route 2A was a former suffixed extension of CR 2 assigned to Dixon Avenue between NY 110 and NY 27 from the 1930s to February 5, 1943[4]
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 3 |
| Length Mi: | 6.84 |
| Length Ref: | [5] |
| Location: | Lindenhurst–Melville |
County Route 3 is a north–south road that includes Wellwood Avenue and Pinelawn Road. It runs mostly parallel to NY 110 until it crosses over the Long Island Expressway, where it moves to the northwest to use NY 110 before its northern terminus with Walt Whitman Road.
As the road intersects an at-grade crossing with the LIRR Central Branch and becomes a divided highway again north of Gear Avenue as it approaches NY 109. North of NY 109, CR 3 runs through the center of the Cemetery zone of southwestern Suffolk County along the following burial grounds;
Before leaving the cemetery zone, CR 3 becomes a divided highway again and passes by the headquarters of Newsday, which also includes the former right-of-way for the Long Island Motor Parkway. Both of these sites are on the southwest corner of CR 3 and CR 5 (Ruland Road). North of unsigned CR 5 (Ruland Road), CR 3 becomes Pinelawn Road, and runs parallel to Old East Neck Road until hitting Half Hollow Road, which leads to the only remaining drivable section of Long Island Motor Parkway (CR 67. From there, CR 3 takes a northwesterly turn and crosses over the Long Island Expressway east of exit 49, where it becomes a four-lane highway again approaching NY 110. CR 3 and Pinelawn Road end just north of NY 110 at Walt Whitman Road. The road continues northward as Sweet Hollow Road as it meanders through the Manetto Hills area past Gwynne Park and West Hills County Park before reaching NY 25, but not as CR 3.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 4 |
| Length Mi: | 9.30 |
| Length Ref: | [6] |
| Formed: | 1930 |
| Location: | North Babylon–Commack |
County Route 4 consists mainly of Commack Road. The road starts at a northeast angle off of NY 231, and immediately has an intersection with Carll's Straight Path to the northwest. The road continues to the northeast as it crosses the Main Line of the Long Island Rail Road. A realigned section exists on the western border of the former Edgewood State Hospital and current Pilgrim State Hospital. The segment in front of Edgewood Hospital was intended to either be replaced by or run parallel to the formerly proposed Babylon–Northport Expressway.
Between the Long Island Expressway and Jericho Turnpike, Commack Road is a four-lane undivided highway with sporadic residential frontage roads. Similar features were installed on parts of Larkfield Road and CR 11 (Pulaski Road).
North of NY 25, CR 4 becomes Townline Road. Though the first two sites consist of churches listed on the National Register of Historic Places, the rest of the area is standard residential suburbia. North of Dovecote Lane, Townline Road runs mostly along the border between the towns of Huntington and Smithtown. New York State Bicycle Route 25A is shared with CR 4 between Burr Road and Scholar Road.
The designation for CR 4 ends at the intersection at Clay Pitts Road in Commack, but the roadway continues northward towards NY 25A in Fort Salonga.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 5 |
| Length Mi: | 1.82 |
| Length Ref: | [7] |
| Location: | Melville–Wheatley Heights |
County Route 5 is a short industrial county route known as Ruland Road and Colonial Springs Road. It runs parallel to a former section of the original Long Island Motor Parkway, beginning at an intersection with New York State Route 110 and heading east. The road passes the headquarters of Newsday and the northern end of Long Island National Cemetery, before terminating just east of the intersection with Little East Neck Road North at the Huntington/Babylon town line in Wheatley Heights.[7]
The route was unsigned for much of its existence. As of January 2024, the route is once again signed.
County Route 6 is Rabro Drive and serves the Hauppauge Industrial Park and the state and county government office buildings. The road begins at an intersection with County Route 108 and proceeds east to New York State Route 111, all within the hamlet of Hauppauge.[8]
County Route 7, better known as Wicks Road, runs south to north from CR 13 to the Long Island Motor Parkway (at the former Long Island Expressway exit 54). The road is entirely in Brentwood.
The road was named for Francis Moses Asbury Wicks (1818-1867), a wealthy landowner and politician who owned the land in the vicinity of the former Thompson's (LIRR station), and later Pine Aire (LIRR station). His home, a large and rambling farmhouse, served as the railroad depot, inn, and general store.
Originally, Wicks Road ran further north than CR 67 onto part of what is today Moreland Road, across the Northern State Parkway to the west side of Hoyt's Farm Town Park, and as far north as NY 25.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 8 |
| Location: | Yaphank–Middle Island |
| Header Type: | former |
County Route 8 was reserved for the never-built Yaphank Bypass. It was intended to be a new four-lane road beginning at the vicinity of exit 66 of the Long Island Expressway, running west of the Carman's River and terminating at CR 21 near Bayliss (Bailey) Road.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 9 |
| Length Mi: | 4.65 |
| Length Ref: | [10] |
| Formed: | 1936 |
| Location: | Huntington–Elwood |
County Route 9, known as Greenlawn Road and Cuba Hill Road, is an unsigned county road that runs through the town of Huntington. The road runs northwest to southeast, beginning as Greenlawn Road and crossing over the Long Island Rail Road as Cuba Hill Road. Its northern terminus is East Main Street (NY 25A) in Huntington, and it ends across from Burr Road at the intersection of Elwood Road (CR 10) in Elwood.
CR 9 serves BAE Systems Long Island, located at the corner of Cuba Hill Road and Pulaski Road (CR 11) in Greenlawn, and James H. Boyd Intermediate School. The section of CR 9 between Little Plains Road and the intersection with Elwood Road (CR 10) is part of New York State Bicycle Route 25A.[10]
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 10 |
| Length Mi: | 3.95 |
| Length Ref: | [11] |
| Formed: | 1955 |
| Location: | Elwood–Northport |
County Route 10, commonly referred to as Elwood Road, is a two-lane suburban county road. It runs from NY 25 in Elwood to NY 25A in Northport.
From the 1950s into the 1980s, there were proposals by the New York State Department of Transportation to build the Babylon–Northport Expressway within the vicinity of the west side of Elwood Road, with interchanges at both ends that included ramps utilizing CR 10. Suburban sprawl and public opposition to the roadway has resulted in the cancellation of the highway.
See main article: County Route 11 (Suffolk County, New York).
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 11 |
| Length Mi: | 11.21 |
| Length Ref: | [12] |
| Formed: | January 27, 1930 |
| Location: | Cold Spring Harbor–Kings Park |
County Route 11, commonly referred to as Pulaski Road, runs west to east between Cold Spring Harbor and Kings Park. CR 11 provides the closest access to the Port Jefferson Branch of the Long Island Rail Road, which runs roughly parallel to the tracks throughout its span in northwestern Suffolk County.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 11A |
| Location: | Greenlawn–East Northport |
| Header Type: | former |
County Route 11A was a former suffixed extension of CR 11 assigned to Pulaski Road between CR 86 and CR 10 from January 26, 1931 to September 21, 1966[4]
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 11B |
| Location: | Huntington Station–Greenlawn |
| Header Type: | former |
County Route 11B was a former suffixed extension of CR 11 assigned to Pulaski Road between NY 110 and CR 86 from December 28, 1931 to September 21, 1966
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 11C |
| Location: | Cold Spring Harbor–Huntington Station |
| Header Type: | former |
County Route 11C was a former suffixed extension of CR 11 assigned to Pulaski Road between NY 108 and NY 110 from November 27, 1933 to September 21, 1966
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 12 |
| Length Mi: | 4.45 |
| Length Ref: | [13] |
| Formed: | 1959 |
| Location: | Amityville–West Babylon |
County Route 12 runs west to east along Oak Street, Hoffman Avenue and Railroad Avenue, parallel to the Babylon Branch of the Long Island Rail Road. It begins at an intersection of CR 1 and Old Sunrise Highway (unsigned NY 900D) and ends at CR 96 at the village of Babylon line in West Babylon.
In Lindenhurst, the name of CR 12 is changed to Hoffman Avenue. However, this name is also shared by a street running parallel to it on the north side of the Babylon Branch maintained by the village. East of the intersection with CR 3, the road passes in front of Lindenhurst Station, while the village of Lindenhurst's Hoffman Avenue runs behind it.
In West Babylon, CR 12's name is changed to South Railroad Avenue, a name it will hold onto upon crossing the border with the village of Babylon. At the border, which is at the intersection of CR 96, is the eastern terminus of CR 12. The roadway east of the terminus reaches NY 109, where it becomes Trolley Line Road, named for the former Babylon Railroad Company, which used the street as part of the route for its streetcar.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 13 |
| Length Mi: | 7.50 |
| Length Ref: | [14] |
| Formed: | 1930 |
| Location: | Bay Shore–Commack |
County Route 13 is a 7.5miles county road that runs north to south from CR 4 near Commack to NY 27A in Bay Shore which includes Fifth Avenue and Crooked Hill Road.. The road runs primarily east of Robert Moses Causeway and Sagtikos State Parkway, until it crosses over the Sagtikos Parkway in the vicinity of Pilgrim State Hospital. The route was added to the county highway system on April 28, 1930, and extensions were made on July 9, 1945.
Past Brook Avenue, the route takes on a more northerly routing as it heads into North Bay Shore and connects to the Heckscher State Parkway at exit 42. Farther north, CR 13 passes by the Entenmann's bakery factory prior to crossing the Main Line of the Long Island Rail Road and intersecting CR 100 (Suffolk Avenue) in Brentwood. The route's run as Fifth Avenue ends just north of CR 100 at a junction with CR 7 (Wicks Road), which continues north from the intersection on the routing established by Fifth Avenue. CR 13, meanwhile, forks to the northwest as Crooked Hill Road.[14]
Not far from CR 7, the route serves both the Pilgrim State Psychiatric Center and Suffolk County Community College's Grant Campus and connects to the Sagtikos State Parkway at exit S2. Crooked Hill Road was originally southbound exit S1 on the Sagtikos Parkway. A traffic circle also existed at the southbound ramps to and from the parkway.[15] When the nearby Long Island Expressway was constructed, the southbound off-ramp was eliminated, but the on-ramp was left intact. The reconstruction of the Long Island Expressway–Sagtikos Parkway interchange from 1988–1991 revived a southbound connection from the parkway to Crooked Hill Road via exit S1W. Today, and as always, Crooked Hill Road is also accessible from exit S2, which connect to roads within the grounds of the Pilgrim State Psychiatric Center, including unsigned CR 106 (Community College Drive).[14]
The route continues on, descending Crooked Hill to reach the Long Island Expressway and its service roads. It crosses under the highway between exits 52 and 53, but has no ramps to or from the main road. Instead, the only access is to the service roads that lead to the expressway westbound and from the expressway eastbound. North of the expressway, CR 13 begins to head in a more north–northeasterly direction that takes it on a largely parallel routing to that of nearby CR 4 (Commack Road). CR 13 ends when the two roads finally converge just south of the Long Island Motor Parkway (CR 67) in Commack.
County Route 13A is the southbound only segment of CR 13 in downtown Bay Shore. At the intersection of Reil Place all southbound traffic along CR 13 shifts to a parallel street called Clinton Avenue. This segment was designated CR 53[17] until May 22, 1967. North of this switch, Clinton Avenue runs parallel to Fifth Avenue as a two-way street, until the intersection with Joseph Avenue, only to be cut off by the interchange with Sunrise Highway. Both CR 13 and CR 13A cross the LIRR Montauk Branch and intersect with CR 50 (Union Boulevard) before terminating at NY 27A.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 14 |
| Length Mi: | 3.22 |
| Length Ref: | [18] |
| Formed: | 1930 |
| Location: | Commack–Kings Park |
County Route 14 is a county highway running south to north from NY 25 (Jericho Turnpike) in Commack to NY 25A in Kings Park. It runs parallel to the east of Sunken Meadow State Parkway. CR 14 ends at NY 25A near Kings Park Station, just two blocks east of CR 11. North of NY 25A, the road turns into Church Street, then Kohr Road, and runs along the east side of Sunken Meadow State Park until ending at Sunken Meadow Road. CR 14 was first added to the county highway system on January 27, 1930. A portion of former CR 2 (Straight Path) was added to CR 14 on June 22, 1961.
In 1978, New York State Department of Transportation built an interchange to-and-from the northbound lane of the Sunken Meadow State Parkway, in order to prevent accidents from motorists trying to cross NY 25 in order to get to CR 14 at exit SM3 E. This interchange was designated exit SM3A. West-to-northbound motorists from NY 25 use the on-ramp from this newer interchange to get to the parkway.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 15 |
| Length Mi: | 1.35 |
| Formed: | 1930 |
| Location: | Smithtown |
| Header Type: | former |
County Route 15, Maple Avenue, was an unsigned, 1.35miles county highway in Smithtown. The route began at an intersection with NY 111 to NY 25 and NY 25A (Main Street). CR 15 was added to the county highway system on January 27, 1930 and is no longer recognized by the Suffolk County Department of Public Works nor the New York State Department of Transportation.[19]
See main article: County Route 16 (Suffolk County, New York).
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 16 |
| Length Mi: | 15.90 |
| Formed: | 1930 |
| Location: | Village of the Branch–Brookhaven |
County Route 16 is a 15.9miles county-maintained highway stretching from NY 25 in Village of the Branch eastward to Montauk Highway (CR 80) in Brookhaven consisting of part of five roads: Terry Road, Smithtown Boulevard, Lake Shore Drive (formerly East Lake Terrace), Portion Road, and Horse Block Road. CR 16 has been in the Suffolk County highway system since January 27, 1930.
Though CR 16 has run consistently from the Town of Smithtown to the Town of Brookhaven since the mid-1960s, this was not always the case. Many segments have been part of other county roads. Lake Shore Drive and Portion Road used to be part of CR 19 from the Smithtown–Brookhaven town line to Waverly Avenue in Farmingville. In 1960, this terminus was moved to Patchogue–Holbrook Road. The construction of Sunrise Highway in 1957 lead to the realignment of Horseblock Road west of its original eastern terminus with South Country Road (former Montauk Highway) in South Haven. Because the interchange is shared with CR 21, the new alignment was originally designated as CR 21A. Horse Block Road used to be a western extension of CR 56 between Victory Avenue, a frontage road along Sunrise Highway that begins at CR 46, in Brookhaven and Waverly Avenue in Farmingville. In 1964, it was moved only to Victory Avenue.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 17 |
| Length Mi: | 5.53 |
| Length Ref: | [20] |
| Formed: | 1966 |
| Location: | East Islip–Hauppauge |
County Route 17 is a 5.53miles county road located in western Suffolk County. The route runs south-to-north from NY 27A in East Islip to NY 111 in Hauppauge, just south of exit 56 on I-495 (the Long Island Expressway). Originally, CR 17 was an alignment of NY 111 (designated as State Highway 1208 internally). On September 13, 1966, the alignment was transferred from the state to Suffolk County and redesignated CR 17. The exit with the Heckscher State Parkway was added in the early 1990s.
North of Suffolk Avenue, CR 17 moves northwest onto Wheeler's Road. This section kept its given name while NY 111 was renamed "Wheeler Road" in order to distinguish the state route from CR 17. From there, CR 17 crosses County Road 67 (the Long Island Motor Parkway) and encounters Bridge Road, a side road that mainly runs parallel to Motor Parkway for much of its run south of the Long Island Expressway. The northern terminus is at a fork in the road with NY 111 roughly 250 yards south of I-495. The NY 111/CR 17 intersection has quite a history. It was originally an at-grade interchange with an overhead expressway signpost holding two signs mounted on the corner that could be seen from the Long Island Expressway. The NY 111 shield was moved from one sign to the next in 1966, but the outline of the former NY 111 shield could still be seen on the original sign. Eventually, as the road was downgraded and the area developed, this sign came down. A Texaco gas station was built at the fork in the road in the mid-1970s. It was shortly converted into a Park and Ride for traffic from the Long Island Expressway.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 18 |
| Length Mi: | 3.90 |
| Formed: | 1930 |
| Location: | Sayville–Holbrook |
| Header Type: | former |
County Route 18 was a 3.9miles county highway along Broadway Avenue from east of Sayville to Holbrook. It was an unsigned two-lane arterial spanning from Montauk Highway (CR 85) to CR 19 (Patchogue–Holbrook Road). A former segment of Broadway Avenue called "Old Broadway Avenue" runs east of the segment between Montauk Highway and somewhere south of Sunrise Highway along the border of Sans Soucci Lakes County Park and near a former Girl Scouts of the USA camp. The route was added to the Suffolk County highway system on January 27, 1930.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 19 |
| Length Mi: | 6.76 |
| Length Ref: | [22] |
| Formed: | 1930 |
| Location: | Patchogue–Lake Ronkonkoma |
County Route 19 is a 6.76miles south–north arterial through central Suffolk County. The highway begins at an intersection with CR 65 in Patchogue. It connects several bedroom communities with major highways such as I-495 (the Long Island Expressway) and NY 27. CR 19 terminates at an intersection with CR 16 in Lake Ronkonkoma. The route was added to the Suffolk County highway system on January 27, 1930, and was amended on January 29, 1965.
Leaving the Patchogue area, the road curves slightly left, as Waverly Avenue (unsigned CR 61) leaves CR 19 and continues its north–south route. Just to the north, CR 19 (now Patchogue–Holbrook Road) intersects two more partial-limited access highways. CR 99 (Woodside Avenue), which leads to the IRS center at Holtsville, has its terminus at CR 19 with a traffic signal. Less than a quarter mile to the north, CR 97 (Nicolls Road) passes overhead and has a diamond interchange with CR 19. Now entering Holbrook, the road divides various large bedroom communities. As it nears downtown Holbrook, the road moves onto a new alignment that was built between 1971 and 1973 to bypass the hamlet. After this bypass was built, the old section was renamed Main Street, eliminated between the new section and former CR 18 (Broadway Avenue) and designated CR 19A (now a former route). The new alignment carries four lanes up and over the Long Island Rail Road's Main Line, and was intended to have an interchange with Union Avenue and Main Street. Reassuming its former alignment, CR 19 then crosses the Long Island Expressway (I-495) with another diamond interchange. This interchange was the eastern terminus of the Long Island Expressway until 1971.
After the Long Island Expressway interchange, the highway narrows to just two lanes with center turn lane. The road again takes an S-curve to the west before heading north again. Halfway within this S-curve, CR 19 was originally intended to terminate at the never built "MacArthur Airport Expressway."[25] The character of this northernmost portion of the road is quite different from the rest, as the road has a much lower speed limit and even passes through a school zone roughly a mile before the terminus at CR 16.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 19A |
| Length Mi: | 0.9 |
| Location: | Holbrook |
| Header Type: | former |
County Route 19A was a 0.9miles former segment of CR 19 in Holbrook. When Patchogue–Holbrook Road was realigned, this section was named Main Street. The old alignment goes "around" Holbrook, which was realigned to carry four lanes up and over the Long Island Rail Road's Main Line, which was intended to have an interchange with Union Avenue and Main Street.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 20 |
| Length Mi: | 6.30 |
| Location: | Port Jefferson–Sound Beach |
| Formed: | 1930 |
| Header Type: | former |
County Route 20 was the unsigned designation for a 6.6miles portion of North Country Road from NY 25A in Port Jefferson, just north of the railroad station, to an intersection with NY 25A in Sound Beach. CR 20 was added to the county highway system on January 27, 1930. Until the 1980s, it also included Sheep Pasture Road and Lower Sheep Pasture Road from Stony Brook to Port Jefferson.
CR 20 was shared with New York State Bicycle Route 25 east of Belle Terre Road in Port Jefferson,[26] and ran through most of the Miller Place Historic District.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 21 |
| Length Mi: | 11.70 |
| Formed: | 1930 |
| Location: | Brookhaven–Rocky Point |
County Route 21 is a two-lane, 11.7miles highway running from Brookhaven to Rocky Point. Its southern terminus is at CR 80 south of the interchange between CR 16 and NY 27 (which includes Yaphank Avenue in the interchange) in Brookhaven. The highway heads northward and terminates at an intersection with NY 25A in Rocky Point. CR 21 was added to the Suffolk County highway system on January 27, 1930.
North of the Long Island Expressway, Yaphank Avenue runs on top of the dam for Lower Yaphank Lake before its terminus at East Main Street. Here the historic Homan-Gerard House and Mills can be found on the southeast corner, while the former Yaphank Garage can be found on the southwest corner. CR 21 makes a left turn at the intersection and proceeds through historic Yaphank. East Main Street leads to another historic Long Island road named Moriches–Middle Island Road, which took residents between Rocky Point and The Moricheses long before the automobile was invented, let alone the Suffolk County Highway System. Near Upper Yaphank Lake, CR 21 intersects with West Main Street, at one of two former Yaphank triangles (the other being at Mill Road and Patchogue–Yaphank Road). At this point, CR 21 resumes its northward heading. Also at this point, a former section of the road is visible on land now owned by the Suffolk County Parks Department. It is visible diagonally across the street from and north of a building formerly owned by New York Telephone.
CR 21 meanders through a variety of landscapes as it heads north to Middle Island, including farmland and forest. It passes close to the Carman's River at this point, particularly in the area of Cathedral Pines County Park. This area was notorious as one of the most deadly stretches of the road until safety improvements realigned and modernized the roadway near East Bartlett Road and again north of Longwood Road. Another former section of road called Old Middle Island–Yaphank Road breaks off to the left near CR 21's intersection with NY 25. North of NY 25, the name of the road changes from Yaphank–Middle Island Road to Rocky Point–Yaphank Road. The former alignment of the road continues roughly parallel to the newer road, rejoining it near the intersection of Bayliss Road (also known as Bailey Road). Additionally, a former meander in the road is visible on either side of CR 21 just south of Whiskey Road.
Between Middle Island and Rocky Point, much of CR 21 runs through the Rocky Point Natural Resources Management Area, a major conservation area on land once owned by the Radio Corporation of America. This land was once considered the world's largest radio transmitting field.[27] Here, the road is given a second name of Marconi Boulevard. North of the former RCA Labs, CR 21 runs between a high school and a housing project, before terminating at NY 25A. North of NY 25A, the road turns into Hallock Landing Road as it heads towards the bluffs of the Long Island Sound.
With the construction of exit 57 along Sunrise Highway, which interrupted original sections of both Horseblock Road and Yaphank Avenue, the new section of Horseblock Road was originally designated CR 21A. This designation was eventually integrated into part of CR 16.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 21A |
| Location: | South Haven |
| Header Type: | former |
County Route 21A was a suffixed alternate of CR 21 created during the construction of exit 57 along Sunrise Highway, which interrupted original sections of both Horse Block Road and Yaphank Avenue, The new section was officially part of Horse Block Road, but was eventually deleted, when it was integrated into part of CR 16.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 22 |
| Length Mi: | 2.45 |
| Formed: | 1930 |
| Location: | Jamesport–Northville |
| Header Type: | former |
County Route 22 was an unsigned, 2.45miles north–south county highway known as Manor Lane. The designation ran from NY 25 in the community of Jamesport to an intersection with Sound Avenue, a former alignment of NY 25A,[28] in Northville, just east of now former CR 23. CR 22 began in the Suffolk County highway system since January 27, 1930.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 23 |
| Length Mi: | 1.75 |
| Formed: | 1930 |
| Location: | Aquebogue–Northville |
| Header Type: | former |
County Route 23 was an unsigned, 1.75miles north–south county highway. CR 23, designated Church Lane, began at an intersection with NY 25 (Main Road) in Aquebogue and terminated at an intersection with Sound Avenue in Northville. CR 23 was added to the county highway system on January 27, 1930, and is no longer recognized by either SCDPW or NYSDOT.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 24 |
| Length Mi: | 1.9 |
| Formed: | 1975 |
| Location: | Middle Island–Upton |
| Header Type: | former |
County Route 24 was an unsigned county highway extending from CR 21 (Yaphank–Middle Island Road) in the community of Middle Island to CR 46 (William Floyd Parkway) in Upton. CR 24, designated Longwood Road, also served Cathedral Pines County Park at its western terminus. The route, which was originally named South Manor Road, was added to the county highway system for Suffolk County on March 25, 1975. The route is no longer recognized by the Suffolk County Department of Public Works and the New York State Department of Transportation.
| State: | NY |
| Type: | CR |
| County: | Suffolk |
| Route: | 25 |
| Length Mi: | 11.05 |
| Location: | Center Moriches–Wading River |
| Header Type: | former |
County Route 25 was an 11.05miles north–south two-lane highway running from Center Moriches to Wading River. CR 25 went from the Montauk Highway in Center Moriches to an intersection with NY 25A in the community of Riverhead. The highway was designated on May 1, 1968, from former CR 66 along Brookfield Avenue, Wading River Road and Schultz Road. During the 1970s, the highway was to receive widening and realignment projects west of the existing Wading River Road. The projects were to stretch from exit 69 on the Long Island Expressway (I-495) southward to the Montauk Highway and the western terminus of the Moriches Bypass, designated CR 98. The new section of the road was never built, and the CR 25 designation was eventually removed.
