Thompson Island is first settled by Europeans.

David Thompson establishes a trading post on the island claimed for him in 1621, then disappears in 1628, leaving his widow and infant son behind. Soon after, according to one account, the widow Thompson marries Samuel Maverick, and moves with him first to Chelsea (then Winnisimmet) and then East Boston (then Noddles Island) in 1633.* Thompson Island becomes part of Dorchester in 1635.* John Thompson returns to Boston and exercises his claim to the island in 1648.