The Indians of North Castle were the SIWANOYS, who belonged to the Wappinger Confederacy, and were part of the Algonkian-speaking group.  Their place names and the names of the sachems (chiefs) remain here today:  Sachem Wampus gave his name to Wampus Pond and stream; Sachem Mayano’s name lives on in the Mianus Gorge and River; from Sachem Cokenseko comes Kensico Reservoir and the lost village of Kensico; Cohamong became Coman as in Coman Hill School, and variations of Armonck (the name the Indians called Byram River) undoubtedly gave us Armonk. In 1701 England’s King William III gave his favorite courtiers the Middle Patent (now the eastern part of North Castle) and the West Patent (now the western section).  People from Massachusetts and Connecticut settled the eastern portion (the earliest part), and Quakers from Rye and Long Island gathered around today’s Armonk. North Castle’s name is derived from an Indian encampment located on the hill where the IBM Corporation World Headquarters stands today.  The site was called "North Fort" and because early settlers felt it resembled a castle, it became "North Castle".