New York State Route 125 (NY 125) is a 7.50-mile (12.07 km) north–south state highway located within Westchester County, New York, in the United States. The route begins at an intersection with U.S. Route 1 (US 1) in the Town of Mamaroneck and ends at a junction with NY 22 in the city of White Plains. A section of the route in the city of White Plains is maintained by Westchester County and co-designated as County Route 26 (CR 26). A second county-owned segment exists along the New Rochelle–Scarsdale line as County Route 129. Both numbers are unsigned. NY 125 was assigned as part of the 1930 renumbering of state highways in New York, initially extending from US 1 to Mamaroneck Avenue in White Plains. It was extended north to NY 22 in the mid-1930s.