- Southern Terminus:
- Glen Cove Road (CR 1) at the North Hempstead-Oyster Bay town line
- Northern Terminus:
- Cedar Swamp Road (NY 107) in Glen Head
- 1.89 miles
Slightly north of Northern Boulevard (NY 25A), Nassau CR 1 ends at the North Hempstead-Oyster Bay town line. Glen Cove Road, which carries the CR 1 designation south of this point, becomes a four-lane divided highway under the jurisdiction of the state. There is no posted route number, but it has NY 904 reference markers and a reference route number of 900B. It runs to the northeast and ends at the point where Glen Cove Road intersects Cedar Swamp Road (NY 107). Glen Cove Road continues north of this point into Glen Cove with the designation of NY 107.