The gangs whose names are introduced early in the film (including The Wanderers) were based on real street gangs in the New York City area. However, they did not all exist at the same point in time. Many of the Wanderers did actually belong to a local football team, named "The Stingers".
The "elbow-tit" scene, where Ken Wahl first meets Karen Allen, was shot on Lydig Avenue, one block south of Pelham Parkway, outside of the actual Wanderers' turf, which ranged from Allerton to Burke Avenues.
The Ducky Boys, an actual Bronx gang that was portrayed in the movie, continued in existence through the 1970s. Though portrayed in the movie and Richard Price novel as "killers", neighborhood residents recall the gang as annoying rather than criminal.