N.Y. Indian Law § 43
Every male Seneca Indian of full age residing on the Allegany, Cattaraugus or Tonawanda reservations, whose name shall appear on the last preceding census taken for the purpose of distributing the annuities due to the said Indians, shall be a qualified voter at all elections or meetings of the electors of his nation; and shall be eligible to any office filled thereat, except that the marshals, peacemakers and councilors of the Seneca nation shall be residents of the reservation for which they were chosen, and the peacemakers of the Tonawanda nation shall be chosen from among the chiefs thereof. If any person offering to vote at any such election shall be challenged as unqualified, the presiding officer shall determine by an inspection of such last preceding census, upon his right to vote; and if he is challenged on the ground of not being twenty-one years of age, such officer shall ascertain the fact by the oath of the person offering his vote, or of any other Indian, which oath he is authorized to administer.
N.Y. Indian Law § 43