Wappinger (wŏpˈĭnjər) [key], confederation of Native North Americans of the Algonquian branch of the Algonquian-Wakashan linguistic stock (see Native American languages). In the early 17th cent. they occupied the east bank of the Hudson River from Poughkeepsie to Manhattan Island and ranged E into Connecticut. They were closely related to the Mahican to the north and the Delaware to the southwest, and there is much argument about assigning various groups to any one of the three peoples. The Wappinger, however, included many groups, the most important of which were the Wappinger proper, the Kitchawong, the Sint Sink, the Tankiteke, the Weckquaesgeek, the Manhattan, the Siwanoy, the Nochpeem, and the Mattabesec. The power of the Wappinger confederacy, which numbered about 5,000 at its peak, was broken in a war with the Dutch (1640–45), and gradually they lost their lands and retired to the protection of neighboring tribes. Some joined the Nanticoke, some the Delaware, and some the Mahican. The Wappinger were of the Eastern Woodlands cultural area (see under Natives, North American).