[1] The street consists of upper and lower portions, linked only by a steep pedestrian stairwell.
At St. Nicholas Place, the terrain drops off steeply, forming Coogan's Bluff.
155th Street is carried on the 1,600-foot (490 m) long 155th Street Viaduct, a City Landmark constructed in 1893, that slopes down towards the Harlem River, continuing onto the Macombs Dam Bridge, crossing over (but not intersecting with) the Harlem River Drive.
[2][3] An unconnected lower section of 155th Street runs at ground level under the viaduct, between a dead-end west of Bradhurst Avenue and a service road of the Harlem River Drive.
[4] The New York City Subway serves the upper portion of 155th Street at 155th Street/St.