Anadarko got its name when its post office was established in 1873. The designation came from the Nadarko Indians, a branch of the Caddo, and the "A" was added by clerical error. In 1871, the Wichita Agency was reestablished on the north bank of the Washita River after being destroyed in the American Civil War. The Wichita Agency administered the affairs of the Wichita, Caddo and other tribes. In 1878, the Kiowa-Comanche Agency at Fort Sill was consolidated with the Wichita Agency. In 1901, the federal government allotted the lands of the Kiowa, Comanche and Arapaho Reservations, and opened the surplus land to white settlement. On August 6, 1901, an auction was held for homesteads and town lots. Around 5,000 people were living in "Rag Town" on the east edge of Anadarko awaiting the auction. Although 20,000 people were present for auction day, Anadarko's population dwindled to 2,190 in 1907.]Agriculture has been the principal driver of the local economy, since the Washita Valley has been good for crops and livestock. The second pillar of the local economy has been Indian affairs.