Harding County was established as a county in the Dakota Territory on 5 March 1881, but was not organized at that time. Its name recognized J. A. Harding, who had been Speaker of the House of Dakota Territory. Its boundaries were altered in 1883, in 1889, and in 1894. On 8 November 1898, Harding County was dissolved and its territory assigned to Butte County. However, on 3 November 1908, it was again created (with altered boundaries) from Butte County's area, and on 17 February 1909 its governing organization was completed.