Okla. Stat. tit. 44, § 41

The Militia of the State of Oklahoma shall consist of all able- bodied citizens of the United States and all other able-bodied persons who shall be or shall have declared their intentions to become citizens of the United States, who shall be more than seventeen (17) years of age and not more than seventy (70) years of age, and said militia shall be divided into three (3) classes: The National Guard, the Oklahoma State Guard, and the Unorganized Militia. Laws 1951, p. 115, art. 3, § 1, eff. May 16, 1951; Laws 1957, p. 422, § 1, eff. May 24, 1957; Laws 1968, c. 299, § 1, emerg. eff. May 3, 1968; Laws 1981, c. 136, § 1; Laws 1985, c. 96, § 1, eff. Nov. 1, 1985.