County Route 97 (Suffolk County, New York)

The oldest section of Nicolls Road was built in the early 1960s between NY 25A and the Nesconset–Port Jefferson Highway, now known as NY 347. The railroad bridge that carries the Port Jefferson Branch of the Long Island Rail Road replaced an older and narrower one over a former section of Sheep Pasture Road. Nicolls Road bisected two sections of Oxhead Road between Sycamore Avenue and Hawkins Road. In the mid-1970s,[2] the driveways and pedestrian underpasses around Stony Brook University were relocated in a major reconstruction project.

The next oldest section of Nicolls Road was built on the ground of the former Suffolk Sanatorium, which was converted into the main campus of Suffolk County Community College. Originally, this segment only ran between South Coleman Road and Portion Road (now CR 16). However, it ended up bisecting Horse Block Road. In order to reconnect the western section of Horse Block Road back to Portion Road, two side roads were built: a north–south frontage called Leeds Boulevard and an east–west street called Horse Block Place between Leeds Boulevard and College Road. A cloverleaf interchange with Portion Road was built in 1971, and the south-to-west ramp connected to both directions on Leeds Boulevard. In the fall of 2008, the left turning lanes at Horse Block Place were eliminated to relieve traffic heading towards the college. In from the late 20th Century to present day Nicholls Road is on speculation giving its rights to the NYSDOT as NY State Route 436.

While connecting the two segments, local streets such as Hawkins Road were reconstructed as a frontage road between Pond Path and Wireless Road, while Bette Ann Drive was built as an additional frontage road along the northbound lane west to Mark Tree Road. At the intersection with Hawkins Road and Wireless Road, the southern terminus of the formerly proposed CR 110 (A.O. Smith Turnpike) was intended to be built with an interchange. A.O. Smith Turnpike was to replace Wireless Road, and continue north of NY 347, towards the vicinity of Port Jefferson Harbor leading to a possible bridge to Bridgeport, Connecticut. The interchange with NY 25 was originally built as a widened median intersection that was intended to be a cloverleaf with outer ramps that connected to local streets like North Hammond Road and South Coleman Road, although construction of this interchange had been put on hold for decades.

Along with the merging of the Stony Brook University and Suffolk Community College sections was the 1971 extension south of Portion Road to the Long Island Expressway. The Division Street overpass was built in 1975, four years after the at-grade intersection was built. After years of financial and bureaucratic delays and rampant development, the NY 25 interchange was finally built as New York State's first single-point urban interchange in 1998.[3]

The construction of Nicolls Road south of exit 62 on I-495 required an extension of Long Island Avenue to Union Avenue, which was cut off by the road and turned into on-off ramps for Long Island Avenue. Two long bridges were built over the Long Island Avenue Extension, the LIRR Main Line, and Furrows Road, which was formerly proposed to be built as part of a Central Suffolk Highway designed to reconnect the two broken ends of NY 24 between East Farmingdale and Calverton.

The interchange with NY 27 was originally an intersection that replaced an intersection with Sylvan Avenue, which became a dirt road north of Sunrise Highway. Like the one with NY 25, it was built as a widened median for the purpose of being upgraded into a cloverleaf interchange. In the 1980s it actually was built as a cloverleaf, but to the newly installed service roads along Sunrise Highway, which required the elimination of two nearby roadside parking areas.