M23 SBS (New York City bus)

M23 Select Bus Service
23rd Street Crosstown Line
A Chelsea Piers-bound M23 SBS bus at Park Avenue.
Overview
System	MTA Regional Bus Operations
Operator	New York City Transit Authority
Garage	Michael J. Quill Depot
Vehicle	Nova Bus LFS articulated New Flyer Industries D60HF (articulated)
Livery	Select Bus Service
Route
Locale	Manhattan
Communities served	Chelsea, Flatiron District, Gramercy Park, Kips Bay, Stuyvesant Town–Peter Cooper Village
Start	Chelsea Piers – off West Side Highway near 22nd Street
Via	23rd Street
End	Avenue C and 20th Street
Service
Operates	24 hours
Daily ridership	3,831,755 (2015)
Fare	$2.75 (MetroCard or coins)
Cash	Coins only (exact change required)
Transfers	Yes
Timetable	M23
Route map Chelsea Piers 12th Avenue / 24th Street 11th Avenue / 23rd Street 10th Avenue 9th Avenue 8th Avenue 7th Avenue 6th Avenue Broadway Park Avenue 3rd Avenue 2nd Avenue 1st Avenue / 23rd Street 1st Avenue / 20th Street 20th Street / 20th Street Loop Avenue C / 23rd Street Avenue C / 20th Street ← M22 ← M15 SBS  {{{system_nav}}}  M31→ M34 SBS →

The 23rd Street Crosstown Line is a surface transit line on 23rd Street in Manhattan, New York City, United States. It currently hosts the M23 bus route of MTA's Regional Bus Operations. The M23 runs between Chelsea Piers, along the West Side Highway near 22nd Street, via 23rd Street, to Avenue C and 20th Street in Stuyvesant Town–Peter Cooper Village.

It replaces a street railway called the Twenty-third Street Railway. On November 6, 2016, it became a Select Bus Service (SBS) route.

For most of its length, the M23 uses 23rd Street to travel crosstown. There is a one-block stretch of the route, between 11th and 12th Avenues, that runs along 24th Street; this is because the M23 needs to access a bus loop at Chelsea Piers, which is along the West Side Highway near 22nd Street, but it must use 24th Street since 23rd Street ends at 11th Avenue. The westbound route between Avenue C and 1st Avenue runs along 20th Street because it needs to terminate along Avenue C in Stuyvesant Town–Peter Cooper Village.

The M23 intersects with every New York City Bus line that it encounters along its crosstown route, as well as some New York City Subway stations. Along Avenue C and 20th Street in Peter Cooper Village, in both directions, the M23 shares bus stops with the M9 route. At the intersections of both 20th and 23rd Streets with 1st Avenue, the northbound M15 and M15 Select Bus Service (SBS) has stops on 1st Avenue, close to the M23 stops. The corresponding southbound M15/M15 SBS stops are at 2nd Avenue. The southbound M9 and eastbound M34A SBS share an eastbound run with the M23 between 2nd Avenue and FDR Drive. At 3rd Avenue, the M101, M102, and M103 are all nearby. The northbound M1, M2, and M3 stop on Park Avenue. The 23rd Street station of the IRT Lexington Avenue Line, under Park Avenue, serves the 6 <6> services. At 5th Avenue and Broadway, near Madison Square, there is a transfer to the southbound M1, M2, and M3; the southbound M5, and the 23rd Street station of the BMT Broadway Line (serving the N R W routes).