In 1846 this agency was established to oversee the area of the upper Arkansas River and the upper Platte. In 1855 the agency became responsible for Northern Cheyenne and Arapaho and the Oglala and Sicangu Lakotas. The agency headquarters were located near Fort Laramie in eastern Wyoming and North Platte, Nebraska before they settled at the mouth of Whetstone Creek on the Missouri River. In 1869 the agency was renamed Whetstone and was primarily responsible for the people of Spotted Tail’s band as well as other Sicangu, Oglala, and Miniconjou Lakotas. Oglalas under Red Cloud and others living near Fort Laramie not attached to another agency remained under this agency until 1871, when it was discontinued.