William Morgan (born 1774 – disappeared c. 1826) was a resident of Batavia, New York, whose disappearance and presumed murder in 1826 ignited a powerful movement against the Freemasons, a fraternal society that had become influential in the United States. After Morgan announced his intention to publish a book exposing Freemasonry's secrets, he was arrested on trumped-up charges. He disappeared soon after and was believed to have been kidnapped and killed by Masons from western New York.