St. Nicholas Avenue is a major street that runs obliquely north-south through several blocks between 111th and 193rd Streets in the New York City borough of Manhattan. The route, which follows a course that is much older than the grid pattern of the Commissioners' Plan of 1811, passes through the neighborhoods of Harlem, Hamilton Heights, and Washington Heights. It is believed to follow the course of an old Indian trail that became an important road in the 17th century between the Dutch settlement of New Amsterdam and the British New England Colonies. In the post colonial era, it became the western end of the Boston Post Road. The road became a street when row housing was being built in Harlem during its rapid urban expansion following the end of the American Civil War. St. Nicholas Avenue serves as a border between the West Side of Harlem and Central Harlem. 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. Route North of 169th Street, St. Nicholas Avenue is aligned with the street grid with Wadsworth Avenue one block west (north of 174th Street) and Audubon Avenue one block east. It crosses over the Trans-Manhattan Expressway at 178-179th Streets. The intersection of St. Nicholas with Broadway at 167th Street forms Mitchell Square Park. Below 169th Street, St. Nicholas Avenue cuts at a diagonal to much of the Manhattan street grid, crossing Amsterdam Avenue at 162nd Street and continuing against the grain to West 148th Street. Below 148th, St. Nicholas returns to a rough alignment with the grid, with Convent Avenue one block west and Edgecombe Avenue to the east, down to 124th Street. Below 124th, St. Nicholas Avenue takes a sharp diagonal, crossing Frederick Douglass Boulevard at 121st Street, and Adam Clayton Powell Jr. Boulevard at 116th Street, ending at Lenox Avenue, just north of Central Park. Its 17th-century origin as part of the Eastern Post Road accounts for its non-conformance to the grid pattern proposed by the Commissioners' Plan of 1811. History The street is claimed to follow an old Indian trail called Weekquaeskeek. From early colonial days through the 19th century, it was known as Harlem Lane. Travelers used it for going between New York and northern areas such as Spuyten Duyvil and Kingsbridge. St. Nicholas Avenue is