The best collection of published biographies in Oklahoma is at the Oklahoma Historical Society http://www.okhistory.org/. The Family History Library has several helpful biographical works. There is no statewide biographical index or major manuscript collection. State, regional, and county histories often have biographical sections containing valuable information. Some representative biographical encyclopedias are:
Portrait and Biographical Record of Oklahoma: Commemorating the Achievements of Citizens who have Contributed to the Progress of Oklahoma and the Development of Its Resources. Chicago, Illinois: Chapman Publishing Co., 1901. (FHL book 976.6 D3p; film 874,324.)
Thoburn, Joseph Bradfield. A Standard History of Oklahoma: an Authentic Narrative of Its Development from the Date of the First European Exploration Down to the Present Time, Including Accounts of the Indian Tribes, both Civilized and Wild, of the Cattle Range, of the Land Openings and the Achievements of the Most Recent Period. 5 vols. Chicago, Illinois: American Historical Society, 1916. (Vols. 2-5 on FHL film 1,425,716 items 1-4.)
Hill, Luther B. A History of the State of Oklahoma. 2 vols. Chicago, Illinois: Lewis Publishing Co., 1908. (FHL book 976.6 H2h; film 1,000,353 items 1-2;
fiche 6,051,224.) Volume 2 contains biographies.
Oklahoma Historical Society. Chronicles of Oklahoma (see "Periodicals" section in this outline).
Biographical sketches of residents of Indian Territory (see the “History” section of this outline) are published in: O'Beirne, Harry F. and Edward S. The Indian Territory: Its Chiefs, Legislators and Leading Men. St. Louis, Missouri: C. B. Woodward Co., 1892. (FHL film 989,201 item 2.)
O'Beirne, Harry F. Leaders and Leading Men of the Indian Territory with Interesting Biographical Sketches: Choctaws and Chickasaws. Chicago, Illinois: American Publishers Association, 1891. (FHL film 1,000,354, item 1.)