In a word; eastern Oklahoma. Indian removals in the East began as early as 1817. In 1830, Congress passed the Indian Removal Act, which authorized the U.S. to set aside lands west of the Mississippi River for tribes. In the ensuing years the Five Civilized Tribes (Choctaw, Chickasaw, Creek, Cherokee and Seminole) were moved to the present state of Oklahoma. In 1866 the western half of Indian Territory was ceded to the United States, which opened part of it to white settlers in 1889. This portion became the Territory of Oklahoma in 1890 and eventually encompassed all the lands ceded in 1866. Eventually many other tribes, including the Osage, Comanche, Modoc, Apache, Cheyenne, and Kiowa, were located there too. By 1885 some fifty tribes were settled on lands once promised to the Five Civilized Tribes for “as long as the grass grows and the water flows.” Further demands for Indian land brought the rush of “boomers” and “sooners” beginning in 1889. The Indian Territory and the Territory of Oklahoma were combined in 1906, prior to gaining statehood the following year.
In the Choctaw language “okla” means “people” and “humma” means “red”. Thus, the area would be named Oklahoma Territory, or literally “Territory of the Red People”. Today “The State of Oklahoma” literally means “The state belonging to Red People”.