Winthrop, John, 1606–76, colonial governor in America, b. Groton, Suffolk, England; oldest son of John Winthrop (1588–1649). He was educated at Trinity College, Dublin, became a lawyer, and emigrated to Massachusetts Bay in 1631. He returned to England in 1634 and in 1635 was commissioned governor of the new colony at Saybrook (now Deep River), Conn., just when other towns were being settled in the Connecticut valley; by agreement he was recognized for a year as titular governor of all. In 1646, Winthrop founded New London, and in 1657 and annually from 1659 to 1676 he was elected governor of Connecticut. After the Stuart restoration (1660), he obtained a charter (1662) that led to the union (1664) of Connecticut and New Haven colonies, and he governed the colony with an administration practically independent of England. He gathered a considerable library and by his interest in chemistry and other sciences helped to promote scientific study in the colonies. Elected a fellow of the Royal Society in 1663, he became the first member resident in America.
See biographies by T. F. Waters (1899) and R. C. Black (1966); R. S. Dunn, Puritans and Yankees (1962, repr. 1971).