Ninigret was a sachem of the eastern Niantic Indian tribe in New England at the time of colonization, based in Rhode Island. In 1637, he allied with the colonists and the Narragansetts against the Pequot Indians.

Sachems and sagamores are paramount chiefs among the Algonquians or other Native American tribes of northeastern North America, including the Iroquois. The two words are anglicizations of cognate terms from different Eastern Algonquian languages. Some sources indicate the sagamore was a lesser chief elected by a single band, while the sachem was the head or representative elected by a tribe or group of bands; others suggest the two terms were interchangeable. The positions are elective, not hereditary. Although not strictly hereditary the title of Sachem is often passed through the equivalent of tanistry.