オクラホマ準州
In 1889, the Unassigned Lands were opened for settlement. The passage of the Organic Act in 1890 assigned "No Man's Land" to the new Oklahoma Territory. "No Man's Land" became Seventh County under the newly organized Oklahoma Territory, land was soon renamed Beaver County. Northwestern Oklahoma took its current form when Oklahoma Territory and Indian Territory joined the Union in 1907 as the single U.S. state of Oklahoma.