Onondaga (people), North American tribe belonging linguistically to the Iroquoian family and forming part of the Iroquois Confederacy. The territory they occupied centered about Onondaga Lake in central New York State and extended north to Lake Ontario and south to the Susquehanna River. Their principal village was called Onondaga or Onondaga Castle. This village served as the capital of the Iroquois Confederacy, and the Onondaga were the official guardians of the council fire of the league. The tribe ranked as the chief member of the confederacy. During the American Revolution the Onondaga sided with the British, and after the war most of the tribe immigrated to a reservation on the Grand River, in Canada, where their descendants still live. The rest were placed on reservations in the region of their former territory in Onondaga County, New York. In the 2000 U.S. census about 2,100 people identified themselves as Onondaga only; an additional 1,100 people reported being part Onondaga.