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.

County Route 1

County Route 1 is known as County Line Road and extends for 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.

Major intersections

County Route 2

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.

Major intersections

County Route 2A

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

County Route 3

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.

Route description County Route 3 begins as Wellwood Avenue on the Lindenhurst village line at Perry Street in North Lindenhurst, which quickly encounters a cloverleaf interchange with NY 27, where the road briefly becomes a four-lane divided highway until the intersection of Spieglehagen Street and becomes a four-lane undivided highway. The road divides again at CR 2 (Straight Path), and includes a northwest to northeast turning ramp. The divider ends at June Street, and the road returns to a four-lane undivided highway.

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; Mount Ararat Cemetery on the west side between NY 109 and Southern State Parkway. New Montifeore Cemetery on the northeast corner of the Southern State Parkway interchange. Roman Catholic Church Diocese of Brooklyn Cemetery on the west side from Southern State Parkway(exit 35) to the Main Line of the LIRR. Wellwood Cemetery on the east side north of Patton Avenue. Beth Moses Cemetery on the east side north of Wellwood Cemetery. Pinelawn Cemetery on the north site of the LIRR Main Line and northeast corner of Pinelawn Station. Long Island National Cemetery on the east side north of Pinelawn Cemetery.

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.

Major intersections

County Route 4

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.

Major intersections

County Route 5

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 in Melville 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 Melville–Wheatley Heights line.

The route was unsigned for much of its existence. As of January 2024, the route is once again signed.

Major intersections

County Route 6

County Route 6, known as Rabro Drive, 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.

Major intersections The entire route is in Hauppauge.

County Route 7

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.

Major intersections The entire route is in Brentwood.

County Route 8

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.

County Route 9

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.

History The Greenlawn Road portion of CR 9 was formerly CR 34 and was reassigned in 1930. The expansion of CR 9 led from the Long Island Rail Road tracks to CR 10, Elwood Road. This expansion, today, is known as Cuba Hill Road, and was added on December 26, 1936. CR 34 was appended onto CR 9 sometime after the 1960s. The road is currently unsigned; however, there were once signs that marked CR 9.

Major intersections

County Route 10

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.

Major intersections

County Route 11

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, since it runs roughly parallel to the tracks throughout its span in northwestern Suffolk County.

County Route 11A

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

County Route 11B

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

County Route 11C

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

County Route 12

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.