entire highway within city limits is maintained on a daily basis by the New York City Department of Transportation. The concurrency between US 9 and NY 9A runs for within the city of Yonkers. All of NY 9A within Yonkers is maintained by the city. NY 9A separates from US 9 along Ashburton Avenue and heads north as Saw Mill River Road. It parallels the Saw Mill River Parkway through Ardsley and Elmsford, to the west side of Hawthorne. The route meets the southbound New York State Thruway (I-87) at a partial interchange and later meets I-287 (the Cross-Westchester Expressway) at a full interchange that provides a route to the northbound Thruway (I-87). NY 100 merges with NY 9A to form a concurrency carrying the names Saw Mill River Road and Briarcliff–Peekskill Parkway, parallel to the Taconic State Parkway. NY 9A exits off this highway along the Briarcliff–Peekskill Parkway, while NY 100 continues straight as Saw Mill River Road. NY 9A merges to form a brief concurrency with US 9 as the Croton Expressway in Ossining just south of the Croton River. The second concurrency between US 9 and NY 9A runs for 1.10 miles, with NY 9A leaving the Croton Expressway at NY 129 in Croton-on-Hudson. The highway heads north along Riverside Avenue and eventually joins old Albany Post Road. After crossing US 9 once more in Cortlandt, NY 9A ends at the Welcher Avenue interchange in southern Peekskill. History Origins Prior to the establishment of the U.S. Highway System, US 9 was designated as NY 6. An alternate route from Yonkers to Tarrytown was assigned the NY 6A designation by 1926. This ran along the present alignment of NY 9A from Yonkers to north of Elmsford, where it turned west on Old Saw Mill River Road, Neperan Road, County House Road and Bedford Road to end at NY 6 in Tarrytown. NY 6 was redesignated as US 9 when U.S. Highways were first posted in New York in 1927; however, NY 6A was not renumbered at this time. It was finally renumbered to NY 9A as part of the 1930 renumbering of state highways in New York. New York City initially did not mark numbered routes within its limits. In 1932, the New York Automobile Club drafted a plan establishing alignments for several routes through the city. In this plan, NY 9A went south through the Bronx and