It’s thought that Captain William Lynch (1742–1820), a farmer from Pittsylvania County, Virginia during the Revolutionary war organized groups of local townfolk– later called “Lynch Mobs” — to provide justice to British collaborators. It is said that sometimes this resulted in a hanging or “Lynching” or a non-trial form of justice.
However, the term “Lynch’s Law” was used as early as 1782 by a prominent Virginian named Charles Lynch (1736 – 1796) to describe his actions in suppressing a suspected Loyalist uprising in 1780 during the American Revolutionary War and those who followed in his footsteps were part of the “Lynch mob.”
According to the American National Biography:
What was purported to be the text of the Pittsylvania agreement was later printed in the Southern Literary Messenger (2 [May 1836]: 389). However, the Pittsylvania County alliance, if it was formed at all, was so obscure compared to the well-known suppression of the uprising in southwestern Virginia that Charles Lynch‘s use of the phrase makes it seem most probable that it was derived from his actions, not from William Lynch‘s.
It has been suggested since then that Edgar Allan Poe is the perpetrator of the story that Captain William Lynch rather than Charles Lynch was responsible for the term “lynch mob.”
Historically Speaking 