Lemuel Hopkins was born on June 19, 1750 in Waterbury, Connecticut, United States. He was the son of Stephen Hopkins by his second wife, Dorothy, the daughter of James Talmadge of New Haven, Connecticut. He was a descendant of John Hopkins who settled in Cambridge, Massachussets, in 1634, removing to Hartford in 1636. The latter's grandson, John, was one of the original proprietors of Waterbury, where he ground the people's corn, ran the tavern, and was a dignitary in the church. His grandson, Stephen, was a well-to-do farmer, who made his sons work in the field, but gave them a good education.