- Southern Terminus:
- Montauk Highway (CR 80) in East Patchogue
- Northern Terminus:
- Sills Road and Long Island Avenue in Yaphank
- 5.32 miles
CR 101 is a north/south running diagonally from Montauk Highway (CR 80) in East Patchogue to just north of the Long Island Expressway (I-495) in Yaphank. The entire length is a four-lane road. It is divided for most of its length, except for the section south of Sunrise Highway (NY 27).
The section of Sills Road north of the expressway was proposed to become CR 64, but it was never taken over by the county and remains a local road.