Dewey County, Oklahoma: History
Lands assigned to the Choctaw and Seminole tribes extended into the area now occupied by Dewey County. Under the Reconstruction Treaties of 1866 the Choctaw and Chickasaw ceded their western domain to the United States. Known as the Leased District, part of the area became the Cheyenne and Arapaho reservation.
Dewey County was created in Oklahoma Territory in 1891 and was opened to non-Indian settlement on April 19, 1892. It was then named as County D by an act of Congress, and did not receive its present name until a general election in 1898. A wooden structure in Taloga was used as the county courthouse from 1909 until 1926, when the present courthouse was built.