M (New York City Subway service)

The M Queens Boulevard/Sixth Avenue Local is a rapid transit service in the B Division of the New York City Subway. Its route emblem, or "bullet", is colored orange since it is a part of the IND Sixth Avenue Line in Manhattan.

The M operates 24 hours daily, although service patterns vary based on the time of day. Weekday rush hour and midday service operates between 71st Avenue in Forest Hills and Metropolitan Avenue in Middle Village, Queens and makes all stops along the full route through Manhattan and Brooklyn; weekday evening and weekend daytime service short turns at Essex Street on the Lower East Side of Manhattan and does not operate to or from 71st Avenue. Overnight service operates as a shuttle between Metropolitan Avenue in Queens and Myrtle Avenue–Broadway in Brooklyn.

The M is the only service that travels in the same borough via two different and unconnected lines. Additionally, the M is the only non-shuttle service that has both of its full-run terminals in the same borough (Queens). Though the full route length between 71st Avenue and Metropolitan Avenue is about 18.2 miles (29.3 km), the stations are geographically located 2.47 miles (3.98 km) apart, marking this as the shortest geographic distance between termini for any New York City Subway service that is not a shuttle service.

An MJ service ran the entire BMT Myrtle Avenue Line until 1969, when the section west of Broadway in Brooklyn was demolished. Before 2010, the full-length M ran from Middle Village to southern Brooklyn via the BMT Nassau Street Line and Montague Street Tunnel. The M had originally ran on the BMT Brighton Line to and from Coney Island–Stillwell Avenue. Beginning in 1986, it used the BMT Fourth Avenue Line and BMT West End Line in Brooklyn, terminating at Ninth Avenue or Bay Parkway.