- Western Terminus:
- Saw Mill River Road (NY 9A) in Ardsley
- Eastern Terminus:
- Tarrytown Road (NY 119) in White Plains
- 2.88 miles
Dobbs Ferry Road is a short east/west route extending from Ardsley to White Plains. It begins at Saw Mill River Road (NY 9A) and runs east for a couple of miles to Tarrytown Road (NY 119). Along the way, there is an interchange with the Sprain Parkway. Despite being a letter-suffixed route, NY 100B does not intersect its parent route, NY 100, although it ends a few blocks to the west of it.