Sagtikos State Parkway

The Sagtikos State Parkway (known colloquially as "the Sag") is a 5.14-mile (8.27 km) controlled-access parkway in Suffolk County on Long Island, New York, in the United States. It begins at an interchange with the Southern State and Heckscher Parkways in the hamlet of West Islip and goes north to a large cloverleaf interchange with the Northern State Parkway in the Town of Smithtown, where the Sagtikos ends and the road becomes the Sunken Meadow State Parkway. The parkway comprises the southern half of New York State Route 908K (NY 908K), an unsigned reference route, with the Sunken Meadow State Parkway forming the northern portion.

The Sagtikos Parkway was proposed by the Long Island State Park Commission to help bridge a gap in the eastern part of the Long Island Parkway system. Construction began in 1949 with the opening of an interchange between Bay Shore Road and the Southern State Parkway. Work on the parkway itself began the following year, with plans calling for connections to three spurs: the Captree State Parkway (now Robert Moses Causeway), the Sunken Meadow Spur (Sunken Meadow State Parkway), and the Heckscher Spur (Heckscher State Parkway). The parkway was completed in 1952, closing the highway loop on Long Island.

As is the case with most other parkways in New York, commercial vehicles are prohibited from using the Sagtikos State Parkway.

The Sagtikos State Parkway begins at an interchange with the Southern and Heckscher state parkways in the hamlet of West Islip, just north of the Robert Moses Causeway's junction with the Southern State Parkway. Heading southbound, this junction is signed as exit S4. The parkway proceeds northward through the Town of Islip as a four-lane divided highway, passing through residential parts of the adjacent hamlet of Brentwood to reach exit S3, a partial cloverleaf interchange with Pine Aire Drive. Just north of the junction, the highway passes over the Main Line of the Long Island Rail Road. Continuing northward through Islip, the Sagtikos Parkway leaves Brentwood ahead of exit S2, a connection to County Route 13 (CR 13, named Crooked Hill Road). The southbound exit serves CR 13 by way of access roads through the Pilgrim Psychiatric Center while the northbound direction uses part of G Road to reach CR 13 and Suffolk County Community College's Grant Campus.

Past the exit, the Sagtikos State Parkway crosses under CR 13 and immediately reaches the Sagtikos Interchange at exit S1 – a large, modified cloverleaf interchange with the Long Island Expressway (Interstate 495). The junction brings the parkway into the Town of Smithtown, where it bends northwestward and parallels CR 67 (Vanderbilt Motor Parkway) for a half-mile (0.8 km) through the town's Commack section. CR 67 eventually turns westward to pass over the Sagtikos Parkway, at which point the parkway curves back to the north and enters exit SM1E, a cloverleaf interchange serving as the Northern State Parkway's exit 44. The Sagtikos State Parkway name ends here while the highway continues northward toward Long Island's North Shore as the Sunken Meadow State Parkway.

According to annual average daily traffic counts compiled in 2011 by NYSDOT, the most-traveled stretch of the Sagtikos State Parkway was the portion between the Southern State Parkway and the Long Island Expressway. The part between the Southern State and Pine Aire Drive handled an average of 87,250 vehicles per day; slightly lower numbers were recorded along the segment between Pine Aire Drive and the Long Island Expressway, with roughly 85,300 vehicles using the section on a daily basis. The portion between the Long Island Expressway and the Northern State Parkway carries an average of 67,600 vehicles per day. All three segments saw a rise in traffic over the course of the previous decade, with the Pine Aire Drive–Long Island Expressway segment gaining 14,000 vehicles per day during that time.

The Sagtikos State Parkway was first proposed in the 1920s as a connector between the Northern and Southern state parkways. In order to construct the freeway, the heirs of the late David Gardiner, who owned the historic Sagtikos Manor in West Bay Shore, donated 197 acres (80 ha) of land to the Long Island State Park Commission (LISPC). This donation was considered unusual by the commission as it would break up the family's estate, which had been constructed in 1692 and served George Washington in 1780. In addition to this donation, James Fisher, a nearby resident, gave the commission 23.5 acres (9.5 ha) of land north of the Gardiner property and another 0.3 acres (0.12 ha) north of the Fisher property to ensure that LISPC had the necessary right-of-way for the new parkway.

The right-of-way on which the parkway was built had originally been part of a private road leading to Sagtikos Manor. The parkway was designed to have connections with the Sunken Meadow Spur (the future Sunken Meadow State Parkway) and the Captree State Parkway (now known as the Robert Moses Causeway) proposed by New York City urban planner Robert Moses. On November 13, 1949, a new interchange between the Southern State Parkway and Bay Shore Road was opened to traffic. This interchange would eventually serve as the Southern State Parkway's junction with the Sagtikos, Heckscher and Captree state parkways. Proposals conceived at this time called for grading on the new Sagtikos State Parkway to begin in early 1950.