Organizations established in the 1860s

The American Mafia, commonly referred to in North America as the Italian-American Mafia, the Mafia, or the Mob, is a highly organized Italian-American criminal society and organized crime group. The terms Italian Mafia and Italian Mob apply to these US-based organizations, as well as the separate yet related Sicilian Mafia or other organized crime groups in Italy, or ethnic Italian crime groups in other countries. These organizations are often referred to by its members as Cosa Nostra ("Our Thing" or "This Thing of Ours") and by the American government as La Cosa Nostra (LCN). The organization's name is derived from the original Mafia or Cosa Nostra, the Sicilian Mafia, with "American Mafia" originally referring simply to Mafia groups from Sicily operating in the United States.

The Hook Gang was a street gang, and later a band of river pirates, active in New York City in the 1860s and 1870s. The gang was prominent in the Fourth Ward and Corlear's Hook districts immediately after the American Civil War, until their breakup by the New York City Police Department in 1876.

Torrey Botanical Society (formerly Torrey Botanical Club) was started in the 1860s by colleagues of John Torrey. It is the oldest botanical society in the Americas. The Society promotes the exploration and study of plant life, with particular focus on the flora of the regions surrounding New York City. Members of the group including Nathaniel Lord Britton and his wife Elizabeth Gertrude Britton founded the New York Botanical Garden.

Zwi Migdal (Yiddish: צבי מגדל, Polish: Cwi Migdał) was a criminal organisation founded by Jews in Poland in the 19th century, based mainly in Argentina.