Jonathan Marsh (1621–1672) was a founding settler of the New Haven Colony, and of Norwalk, Connecticut. He came to Norwalk from New Haven sometime prior to March 1656. He was the settlement's miller. He was born about 1621, in Braintree, Essex, England, the son of John Marsh and Grace Baldwin. Jonathan and his brother Samuel came to America from England, and are recorded in Boston in 1641. On May 7, 1650, he is recorded as having sold his land in New Haven to Lancelot Fuller who was married to Jonathan's sister Hannah Marsh. Marsh sold his lot to Ephraim Lockwood in 1664.