- Western Terminus:
- Somerstown Road (NY 100) in Somers
- Eastern Terminus:
- North Salem Road (NY 121) in North Salem
- 5.19 miles
NY 138 is a short east/west route in the northern portion of Westchester. It begins at Somerstown Road (NY 100) and runs southeast to Goldens Bridge, where it has a partial interchange with I-684. It continues east for several miles to end at North Salem Road (NY 121).