Anadarko OK. Complete information about Anadarko, city in Caddo County, Oklahoma, United States. Updated news about the city, Anadarko Petroleum, High School, Internet Technology and much more! Anadarko is the capital of the  American Indian Exposition, held annually during the first full week in August at the Caddo County Fairgrounds in Anadarko, Oklahoma, is one of the oldest and largest intertribal gatherings in the United StatesDo not miss our feature pages, special sections and complete the survey of visitors.