The Italian American Mafia began at the time when many Italians immigrated to the United States and made it their home in the 1800s. The American branch of the mafia is believed to have begun in 1893 when Don Vito Cascio Ferro fled to New York after the murder of banker Emanuele Notarbartolo, in Sicily..The Italian mafia in the United States is sometimes referred to as La Cosa Nostra which is Italian for "Our thing". They continues to dominate organized crime in the United States. It uses this status to maintain control over much of Chicago, Detroit, Boston, Buffalo, Pittsburgh, Cleveland, Philadelphia, Providence, New Jersey and New York City's organized criminal activity.

The American mafia is divided into different groups or "families". Many large cities have one Italian mafia family but some larger cities like New York City have more. The New York Mafia has five families. They consist of the Bonanno, Colombo, Gambino, Genovese and Lucchese families. Much like The Godfather, which portrayed a romanticized version of the Mafia, their have been times when mafia families had gone to war with each other. (a term used for such is "hitting the mattresses".) Local Police, State Police, and Federal law enforcement have cracked down heavily on the Mafia in New York over the past decade taking down much of the leadership including John Gotti and his crew.