Adriaen (Arjan) Block (c. 1567 – buried April 27, 1627) was a Dutch private trader, privateer, and ship's captain who is best known for exploring the coastal and river valley areas between present-day New Jersey and Massachusetts during four voyages from 1611 to 1614, following the 1609 expedition by Henry Hudson. He is noted for possibly having named Block Island, Rhode Island, and establishing early trade with the Native Americans, and for the 1614 map of his last voyage on which many features of the mid-Atlantic region appear for the first time, and on which the term New Netherland is first applied to the region. He is credited with being the first European to enter Long Island Sound and the Connecticut River, and to determine that Manhattan and Long Island are islands.