The Ninth and Tenth Avenues Line or Ninth Avenue Line is a surface transit line in the New York City borough of Manhattan, running mostly along Ninth Avenue and Amsterdam Avenue from Lower Manhattan to Manhattanville. Originally a streetcar line operated by the Manhattan and Bronx Surface Transit Operating Authority, it is now the M11 bus route operated by the New York City Transit Authority.

Ninth Avenue, known as Columbus Avenue between West 59th and 110th Streets, is a thoroughfare on the West Side of Manhattan in New York City, United States. Traffic runs downtown (southbound) from the Upper West Side to Chelsea. Two short sections of Ninth Avenue also exist in the Inwood neighborhood, carrying two-way traffic.