St. Nicholas Avenue is a major street that runs north-south between 193rd Street and 111th Streets in the New York City borough of Manhattan. It goes through the neighborhoods of Harlem, Hamilton Heights, and Washington Heights. St. Nicholas Avenue serves as a border between the West Side of Harlem and Central Harlem. Although Harlem in a broad sense spans from the East River to the Hudson River, the area west of St. Nicholas Avenue is not always counted as part of Harlem proper.
The IND Eighth Avenue Line runs under St. Nicholas Avenue north of 121st Street as far as 168th Street, and is sometimes referred to as the St. Nicholas Avenue Line.