New York State Route 120A (NY 120A) is a state highway in southern Westchester County, New York, in the United States. It serves as an alternate route to the southern half of NY 120 running along the New York–Connecticut state line. The southern terminus of the route is at NY 120 in Harrison. Its northern terminus is at NY 120 in North Castle. Most of the 8.55-mile (13.76 km) route straddles the New York–Connecticut state line, and part of the route is physically located in Connecticut. However, this part of the highway is not recognized by Connecticut as "Route 120A", and is considered to be part of NY 120A by the New York State Department of Transportation (NYSDOT).