Prospect Expressway and Linden Boulevard

NY 27 begins at exit 24 of I-278 (the Gowanus Expressway) in the borough of Brooklyn in New York City. For the first stretch through Brooklyn, NY 27 runs along the Prospect Expressway — a sunken six-lane freeway through the Park Slope and Windsor Terrace neighborhoods — providing interchanges with Fourth Avenue, Seventh Avenue, and 11th Avenue. At exit 5, eastbound NY 27 leaves the Prospect Expressway; the highway interchanges with Ocean and Fort Hamilton Parkways before ending a short distance to the south at exit 6 and Church Avenue.^[4] Eastbound NY 27 follows East 5th Street to Caton Avenue; westbound NY 27 leaves Caton Avenue at Coney Island Avenue, then follows Church Avenue to the Prospect Expressway.^[5]

NY 27 runs along Caton Avenue near the south end of Prospect Park in Flatbush. A short distance east, the street merges into Linden Boulevard, crossing eastward through Brooklyn on Linden. NY 27 passes east through East Flatbush and reaches a large intersection with Kings Highway and Remsen Avenue, where it expands into a six-lane boulevard through Brooklyn with frontage roads. East of East 96th Street, NY 27 intersects Rockaway Parkway and then travels under the BMT Canarsie Line, winding through New Lots before turning northeast. After crossing under a nearby subway yard, the boulevard passes through the City Line neighborhood. Near the junction with Ruby Street, NY 27 enters the borough of Queens, but retains the Linden Boulevard name.^[4]

Conduit Avenue

Continuing northeast through Queens, NY 27 and Linden Boulevard enter Ozone Park and reach an interchange with Conduit Avenue, where Linden Boulevard ends. NY 27 then continues eastward along the divided Conduit Avenues. This portion of the route becomes a controlled access highway, coterminous with the western portion of Nassau Expressway (NY 878) starting at Cross Bay Boulevard until Aqueduct Road.^[6] (When constructed, the portion from Linden Boulevard until what is now Aqueduct Road, was designated Sunrise Highway. This is not to be confused with present Sunrise Highway, which is at the other end of Queens. Sunrise became Conduit at 111th Street, which no longer exists, but is approximately where Aqueduct Road currently crosses over Route 27.)^[7][8]

When the Nassau Expressway splits off, NY 27 continues east along Conduit Avenue and remains a frontage road for multiple exits of the Belt Parkway. The route interchanges with I-678 (the Van Wyck Expressway) a short distance later.^[4]

NY 27 remains a frontage road entering Springfield Gardens, crossing multiple exits of the Belt Parkway until entering Laurelton. In Laurelton, the Belt Parkway turns northward while NY 27 continues eastbound as South Conduit Avenue and westbound as Sunrise Highway, but stays a seven-lane divided boulevard (four eastbound and three westbound). The route crosses Francis Lewis Boulevard and south of the Rosedale Long Island Rail Road station; just east of Hook Creek Boulevard, NY 27 enters Nassau County and becomes the Sunrise Highway.^[4]

Sunrise Highway

Sunrise Highway begins as a six to eight-lane arterial road in eastern Queens, directly paralleling the Atlantic and Montauk branches of the Long Island Rail Road. It heads east into Nassau County, passing through Valley Stream, Lynbrook, and Rockville Centre on its way to Merrick. There it connects to the Meadowbrook State Parkway by way of an interchange. NY 27 continues to Wantagh, where it has an interchange with the Wantagh State Parkway. One mile (1.6 km) later, the highway has an interchange with NY 135 in Seaford. In East Massapequa, NY 27 passes under the LIRR and ends its stretch through Nassau.

NY 27 then enters Suffolk County, where it veers to the northeast, bypassing Copiague. At the interchange with NY 109 in West Babylon, Sunrise Highway becomes a six-lane freeway with a two-lane service road on either side. The route then meets the Robert Moses Causeway near West Islip. In East Patchogue, New York, the highway is reduced to a four-lane freeway after passing the NY 112 exit.

Between County Route 16 (CR 16) in Brookhaven and CR 46 in Shirley, the median is lined with pine trees along South Haven County Park. The setting along these roads is similar to the one on the Southern State Parkway west of Belmont Lake State Park. The last exit with a state highway is near Hampton Bays, where it meets NY 24.

East of NY 24, Sunrise Highway crosses over the Shinnecock Canal and has one last eastbound exit before merging with CR 39. It changes names to North Highway, a four-lane undivided highway more commonly known as the Southampton Bypass. The highway continues east near toward village of Southampton before ending at an intersection with Montauk Highway. NY 27 turns east at that junction, following Montauk Highway toward Water Mill and points east.

Montauk Highway

The section of Montauk Highway over which NY 27 runs is two lanes wide, with the exception of the four-lane sections in the village of East Hampton. This section of NY 27 is concurrent with New York State Bicycle Route 27. NY 27 heads generally northeastward to East Hampton village where it becomes Woods Lane, and later, Main Street. It has an intersection with the southern end of NY 114 before entering downtown. After passing Newtown Lane and North Main Street, NY 27's name changes to Pantigo Road, as it passes an eponymous historic district, listed on the National Register of Historic Places.^[9]

In the hamlet of Amagansett, NY 27's name changes back to Main Street, again returning to the Montauk Highway name. The road becomes Montauk Point State Parkway as it enters Hither Hills State Park in Napeague. The parkway, a Robert Moses-designed highway, carries NY 27 to its eastern terminus at Montauk Point State Park, on the east side of Montauk. The final 10 miles (16 kilometers) of NY 27 is known as Montauk Point State Parkway.

Designation and early realignments

NY 27's designation was assigned in the mid-1920s to a road extending from the New York City line to Amagansett.^[2][3] It began at the point where Merrick Road exited Queens and entered Nassau County. It mostly followed Merrick Road and Montauk Highway east to Amagansett. From East Patchogue to Brookhaven, NY 27 followed South Country Road, passing through the downtown section of the village of Bellport.^[3][10] The NY 27 designation was extended eastward along Montauk Highway to Montauk Point by 1930.^[11]

On February 24, 1930, South Country Road was added to the Suffolk County highway system as CR 36.^[12] NY 27 was subsequently realigned to follow Montauk Highway between East Patchogue and Brookhaven.^[13]

NY 27 was realigned west of Oakdale c. 1931 to follow Sunrise Boulevard, a new highway parallel to Merrick Road, and then Montauk Highway, between the New York City line and Massapequa connecting several local roads from Massapequa to Montauk Highway at Oakdale. The former routing of NY 27 from Massapequa to Oakdale became NY 27A, connecting to NY 27 in Massapequa by way of County Line Road.^[14][15]

Sunrise Boulevard was extended eastward to Oakdale c. 1934 as a realignment of NY 27.^[16][17] One portion of NY 27's former route between NY 27A in Massapequa and the Suffolk County line is known as Old Sunrise Highway, and remains state-maintained to this day as NY 900D, an unsigned reference route.^[18]

Sunrise Highway was built over the Brooklyn Waterworks aqueduct, past the south side of Aqueduct Racetrack.^[19]

New York City

In December 1934, the route was extended westward into New York City. NY 27 followed Sunrise Highway, Linden Boulevard, and Flatbush Avenue through Queens and Brooklyn to the Manhattan Bridge, where it continued into Manhattan along Canal Street to a terminus at 6th Avenue (then-U.S. Route 1A and later NY 1A).^[20]

The route was realigned slightly in the early 1940s to follow Atlantic and Washington Avenues, Eastern Parkway, Buffalo Avenue, and Rockaway Avenue between Flatbush Avenue and Linden Boulevard.^[21][22] NY 27 was again altered in the mid-1960s to continue west on Linden Boulevard, Caton Avenue, and Church Avenue to the south end of the Prospect Expressway. There, the route turned north, following the freeway to its end at the Gowanus Expressway (then-NY 27A), where NY 27A now ends.^[23][24] The Prospect Expressway was planned by Robert Moses, and was constructed during the 1950s.

Prior to 1970, NY 27A continued north to the Holland Tunnel in Manhattan by way of the Gowanus Expressway, the Brooklyn–Battery Tunnel, and the West Side Elevated Highway.^[23] On January 1, 1970, NY 27A was truncated eastward to its current western terminus in Massapequa while NY 27 was extended northward along NY 27A's former route to the Holland Tunnel, where it ends at I-78 and NY 9A.^[25]

By 1973, NY 27 was cut back to its interchange with the Gowanus Expressway while I-478 was assigned to both the Battery Tunnel and all of the West Side Elevated Highway south of the Lincoln Tunnel.^[26][27]

Long Island

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Robert Moses developed plans for an elevated freeway featuring 10 to 12 lanes along Sunrise Highway through Nassau County. This freeway would have provided a truck link for the South Shore of Long Island but the downtown villages along the route effectively put a stop to the idea.^[28]

The portion of Sunrise Highway between North Lindenhurst and East Patchogue was gradually upgraded to an freeway from the late 1960s until the late 1990s, while the portion between East Patchogue and Shinnecock Hills was built as one from the start, and not upgraded from a surface road like the North Lindenhurst to East Patchogue segment was. The freeway portion of Sunrise Highway between North Lindenhurst and Shinnecock Hills was completed in full in 1998.^[29] At the east end of NY 27 the highway abruptly became a three-lane highway east of the Shinnecock Canal, at the point where NY 27 is concurrent with CR 39. This area was known as the "Shinnecock Squeeze" as traffic on the two-lane eastbound NY 27 was "squeezed" into a single lane.

In 2006 and 2007 Suffolk County and Southampton officials began using traffic cones to adjust the lanes to accommodate peak travel in what was called the "traffic cone program".^[30]

At the end of summer 2007, another eastbound lane was added, heading eastward to North Sea Road. The construction snarled traffic on CR 39. The Long Island Rail Road added three trains each way between Speonk and East Hampton during the construction.^[31] In April 2008, the three-lane segment from North Sea Road to Flying Point Road was reconfigured from one eastbound and two westbound lanes to two eastbound and one westbound lane. The merge from two lanes to one in the eastbound direction is now assisted by a signalized intersection at Flying Point Road, where eastbound NY 27 traffic makes a left turn onto Montauk Highway.^[32] This widening project eliminates the "Shinnecock Squeeze."^[33]