- Southern Terminus:
- Boston Post Road (US 1) in Mamaroneck
- Northern Terminus:
- Cross Westchester Expressway (I-287) in White Plains
- 6.36 miles
NY 127 is a north/south route in Westchester County extending from Mamaroneck to White Plains. It begins at Boston Post Road (US 1) as a two-lane undivided road. The first few blocks are known as Keeler Avenue, and then it changes names to become Harrison Avenue. It runs northeast to Harrison, where it passes over the New England Thruway (I-95) with no interchange. About a mile beyond the highway, Harrison Avenue ends at North Street, which is designated CR 73 south of this point. NY 127 follows North Street to the north. After another mile, there is an interchange with the Hutchinson Parkway. A little bit past the parkway, North Street widens to four lanes with a grass median. In White Plains, North Street splits off to become a one-way local street. NY 127 follows White Plains Avenue for a short distance to end at the Cross Westchester Expressway (I-287).