United States. Bureau of Indian Affairs. Osage Agency

In 1851 the Osage Subagency and the Neosho Subagency were combined to form the Neosho Agency which was responsible for the Osage, Quapaw, Seneca, and Mixed Band of Seneca and Shawnee. This agency was placed under the Southern Superintendency where it remained until transferred to the Western Superintendency in 1867.

An Act of Congress of July 15, 1870 (16 Stat. 335) provided for the removal of the Osages from Kansas to a reservation in the north central part of Indian Territory on land to be purchased from the Cherokees. The Osages agreed to the removal on September 12, 1870, and began arriving on their new reservation in January 1871. Their agent established his headquarters near Silver Lake which is south of the present site of Bartlesville, Oklahoma. However, an error had been made in locating the eastern boundary of the reservation which resulted in a dispute between the Osages and the Cherokees which was eventually settled by an act of Congress of June 5, 1872 (17 Stat. 228) which set the boundaries of the reservation and the purchase price and also required the Osages to sell a tract of land in the northwest corner of their new reservation to the Kaw (Kansa) tribe.

In 1872 the agent established his headquarters at Deep Fork on Bird Creek which is now the site of Pawhuska, Oklahoma. The Neosho Agency was officially renamed the Osage Agency on December 22, 1874, with responsibility for the Osage and Kaw tribes. In 1879 a small band of Quapaws moved onto the reservation and remained there until the late 1880's. A subagency and boarding school were maintained for the Kaw at a site 35 miles west of Pawhuska near the southern border of the Kaw Reservation. On July 1, 1904, the Kaw School and Agency was transferred to the Pawnee Agency.