Philip Patrick Henry Cronin (August 7, 1846 – May 4, 1889) was an Irish immigrant to the United States, a physician, and a member of Clan na Gael in Chicago. In 1889, Cronin was murdered by affiliates of Clan na Gael. Following an extensive investigation into his death, the murder trial was, at the time, the longest-running trial in U.S. history. Cronin's murder caused a public backlash against secret societies, including protests and written condemnations by the leadership of the Catholic Church.