- Southern Terminus:
- Searingtown Road (Nassau CR 101) and Northern Boulevard (NY 25A) in Manhasset
- Northern Terminus:
- Middle Neck Road, Harbor Road, and Astor Lane in Port Washington
- 3.58 miles
Port Washington Boulevard is the main road in Port Washington. It begins at Northern Boulevard (NY 25A) in Manhasset and runs to the north. It begins as a four-lane divided road. When it enters Port Washington, the divider ends. After the intersection with Beacon Hill Road (CR 15), it narrows down to two lanes. NY 101 ends at the intersection with Harbor Road and Astor Lane, where Port Washington Boulevard becomes Middle Neck Road.