Onondaga holds a role no other Haudenosaunee nation shares: rather than sitting as an Elder or Younger Brother, its fourteen chiefs, the largest delegation of the fifty the founding five nations divided among themselves, sit as Firekeepers, hosting the Grand Council's sessions and holding its central council fire and its wampum records. The Tadodaho, the title that presides over the Grand Council itself, is by tradition held by an Onondaga chief, named for the historical Onondaga sachem whom the Peacemaker and Hiawatha are said to have persuaded to support the founding of the confederacy after fierce initial resistance. William Fenton's political history of the confederacy, drawing on both the oral tradition and the written colonial record, traces this Firekeeper role across the whole span from the confederacy's founding to the 1794 Treaty of Canandaigua.
Onondaga territory sits at the geographic center of Haudenosaunee lands, in what is now central New York around present-day Syracuse, a position that mirrors its political centrality. The Onondaga Nation retains a reservation south of Syracuse today, one of the smaller Haudenosaunee land bases in New York but the one that still hosts the Confederacy's Grand Council in practice as it long has by tradition. The Longhouse religion, reformed by the Seneca prophet Handsome Lake in the early nineteenth century, continues to be practiced at Onondaga, and the nation's medicine societies and ceremonial knowledge, like those of the wider Confederacy, are restricted to initiated members rather than published outside them.