The IRT portion of the station is very deep and requires the use of elevators to reach the platform after fare control, which is on a full length mezzanine above the higher IND portion. Another set of elevators connecting the IND platforms and tracks to the mezzanine, and an elevator between the mezzanine to the street, make that portion handicapped-accessible. The IRT section is not ADA accessible since the platforms have no elevators (reaching the elevators to fare control requires climbing short staircases).
In 2005, the station was added to the National Register of Historic Places.
The full-time fare control area is at the center of the mezzanine, and has a turnstile bank, token booth, and one staircase and one elevator going up to the northeast corner of West 168th Street and Saint Nicholas Avenue. The part-time side at the north end of the mezzanine has HEET turnstiles and three staircases, two to the southwest corner of Broadway and 169th Street and one to the northwest corner. An exit-only turnstile in the middle of the mezzanine, near the corridor leading to the IRT platforms, leads to a staircase going up to north end of Mitchell Square Park on the south side of West 168th Street between Broadway and Saint Nicholas Avenue.
The passageway leading to the IRT elevators is just beyond the full-time fare control area. There are two exit stairs past this part-time fare control area, both of which diverge in opposite directions near the southwest corner of Broadway and 168th Street.
There is evidence that there was another passageway outside fare control near the south end of the IND platforms, including two closed off staircases from each platform and street exits to 167th Street. This passageway was closed in the 1980s for safety reasons. This area is now used for New York City Transit employees only.
168th Street on the IRT Broadway–Seventh Avenue Line has two tracks and two side platforms.
The West Side Branch of the first subway was extended northward to a temporary terminus of 221st Street and Broadway on March 12, 1906 with the station at 168th Street not yet open. This extension was served by shuttle trains operating between 157th Street and 221st Street until May 30, 1906 when express trains began running through to 221st Street. The 168th Street station opened for service on April 14, 1906.
In 1948, platforms on the IRT Broadway–Seventh Avenue Line from 103rd Street to 238th Street were lengthened to 514 feet to allow full ten-car express trains to platform. Previously the stations could only platform six car local trains. The platform extensions were opened in stages. On April 6, 1948, the stations from 103rd Street to Dyckman Street had their platform extensions opened, with the exception of the 125th Street, which had its opened on June 11, 1948.
The station was served by Seventh Avenue express trains from 1906 to 1959, after which the station has been served by local 1 trains. From 1989-2005, the 9 service, a skip-stop variant of the 1, went to the station.
This deep station has a high arched tiled ceiling and white globe lights on ornate fixtures hanging from the walls and ceiling on the north half. The south half, where the platforms were extended in the 1950s, has a much lower ceiling and large marble columns with alternating ones having the standard black station name plates in white lettering, but the name tablets and trim line are the same as those on the north half of the station. There is a closed stairway on the extreme northern end of the northbound platform leading to an unknown location.
Near the north end of the station, there are two bridges above the tracks, each of which has two staircases going down to each platform. On the southbound side of the bridges, there are four elevators, one of which is staffed, going up to an unstaffed fare control area where a turnstile bank leads to two staircases going up to the southwest corner of Broadway and West 168th Street. A corridor within fare control leads to the IND mezzanine.
Until 2015, the elevators to the platforms on the IRT Broadway – Seventh Avenue Line still utilized elevator operators, one of the only stations in the system to do so.
168th Street is an express station on the IND Eighth Avenue Line that opened on September 10, 1932, and has four tracks and two island platforms. Contrary to the usual express station layout, the inner tracks serve the C local trains while the outer tracks serve the A express trains. This is to make it easier for C trains to terminate here, and turn around to make the southbound trip to Brooklyn. South of this station, the outer tracks descend to a lower level below the inner tracks, creating a two-over-two track layout. North of the station, the inner tracks continue north under Broadway to 174th Street Yard while the outer tracks turn sharply under Fort Washington Avenue before continuing to Inwood–207th Street.
Both outer track walls have a reddish purple with a black border, but no name tablets, and small "168" signs below them in white numbering on a black border. This station has a full length mezzanine above the platforms and tracks.
The station is planned to be renovated starting in 2016 as part of the 2010–2014 MTA Capital Program. An MTA study conducted in 2015 found that 48% of components were out of date.
When the line opened, this station was served by an AA local train from 168th Street to Chambers Street/World Trade Center. It was discontinued in 1933 when the CC was created to run local along the IND Eighth Avenue and Concourse lines. It was resurrected in 1940 when the BB (later B) was created. The AA, which only ran outside rush hours after 1940, was renamed K in 1985 and completely replaced by the C's midday service on December 11, 1988.
The original BB train, beginning with the opening of the Sixth Avenue Line on December 15, 1940, ran as a rush-hour only local service starting at 168th Street–Washington Heights. The designation "B" was originally intended to designate express trains originating in Washington Heights and going to Midtown Manhattan on the IND Sixth Avenue Line. On March 1, 1998, the B and the C switched northern terminals, ending B service to this station and bringing C trains to this station at all times except late nights.
The A has always served this station since its inception in 1932.
Nearby points of interest include NewYork-Presbyterian Hospital/Columbia University Medical Center, Hudson River waterfront parks, and remnants of the Audubon Ballroom.