Harlem–125th Street station is a commuter rail stop serving the Metro-North Railroad's Hudson, Harlem, and New Haven Lines.

It is the only station besides Grand Central Terminal that serves all three lines east of the Hudson River.

Trains leave for Grand Central Terminal, as well as to the Bronx and the northern suburbs, regularly.

The station was constructed along the Park Avenue main line of the New York Central Railroad.

The current station was built in 1896–97 and designed by Morgan O'Brien, New York Central and Hudson River Railroad principal architect.

The original station on the site was built in 1844, when the trains ran at grade-level on what is now Park Avenue.

Penn Central's continuous financial despair throughout the 1970s forced them to turn over their commuter service to the Metropolitan Transportation Authority.

At the time, it was expected that the renovation would repair the station's leaky roof, install new windows, lighting, and doors, and replace its dilapidated platforms.

[12] The entire Park Avenue viaduct was replaced piece-by-piece without disturbing Metro-North service for the duration of the renovation.

[19] In 2015, a nonprofit organization consisting of local small businesses, property owners and stakeholders called NHEMA (now Uptown Grand Central)[20] adopted this space as a NYC Department of Transportation community plaza, and ever since has programmed the space with activities including a year-round farmers market, pop-up shop featuring local small businesses, concerts, a mobile library and free exercise classes for the community.

Ridership at Harlem–125th Street station rose 55% between 2002 and 2013, much of which included reverse commuters—city residents accessing jobs in the suburbs.