Like many of the roads built by Suffolk County between the 1940s and 1970s, it had the potential to be upgraded into a limited-access highway, but those proposals were thwarted by development and public opposition.

When the New York State Department of Transportation caved into public opposition and cancelled the expressway in 1966, Suffolk County took up the task of improving CR 101 for itself.

The former segment between Hospital Road and Gazzola Drive (formerly part of Sipp Avenue) was left to local residents.

The south side of the bridge over the railroad tracks that replaced the old one also contains a right-of-way for the formerly proposed CR 90 (Central Suffolk Highway).

CR 101 terminates at the northern intersection of another Long Island Avenue, although Patchogue–Yaphank Road continues in a northwesterly direction as it curves towards the heart of Yaphank.

[2] In addition, at the vicinity of the interchange with the Long Island Expressway, there was to be a southern terminus of CR 8 (the proposed Yaphank Bypass).

Much of CR 104 runs through the David Allen Sarnoff Pine Barrens Preserve, a major New York State Conservation Area, that was once owned by Radio Corporation of America.

County Route 106 is a road spanning from Pilgrim State Psychiatric Center to CR 7, which was originally part of the hospital when it had more territory.

The route was proposed to be relocated onto Hubbard's Path and Cadman Avenue as part of its potential transformation into the West Babylon–Centerport Highway.

At the intersection with the Long Island Motor Parkway, CR 108 joins westbound CR 67, while Caleb's Path continues north as a town of Islip road that ends at the eastbound service road of the Long Island Expressway, on the corner of a Greyhound Bus Terminal, which was originally a Texaco gas station.

From here it runs straight north where descends along the Ronkonkoma Moraine, passing by the site of the former Brentwood Mackay Radio Station[6] until it curves northwest again and approaches the next major intersection at NY 454.

The northeast corner of NY 454 and CR 108 is the 4th Precinct of the Suffolk County Police Department, which was once the Smithtown Aviation Country Club until 1957.

Turning straight north again, the road runs through some residential areas until it curves northeast as it approaches Caleb Smith State Park, where the formerly proposed Northern State Parkway extension was supposed to be built a former section of the road that currently enters the park.

Here CR 108 curves back north again and finally terminates at Jericho Turnpike, as does Old Willet's Path, which turns into Plymouth Boulevard, a Town of Smithtown residential street.

A formerly proposed extension was intended to run along Plymouth Boulevard and Old Northport Road, and then would have terminated at CR 11.

[1] County Route 113 is an unmarked street named Stephen Hands Path near the village of East Hampton.

Later it curves northeast again, before reaching a LIPA power line right of way, and then the intersection of Buckskill Road.

The route begins at Shore Road (Nostrand and Brander parkways) and Bootlegger's Alley.

Halfway between CR 115 and the south shore of Shelter Island, CR 116 runs along the east side of West Neck Bay and West Neck Creek, then turns east onto Smith Street, From here it runs close to the north shore of Menatic Creek, then intersects Midway Road.

Burns Road continues east of the terminus of CR 69 to the west shore of Coecles Inlet.