Native Americans forced out of their homelands by white settlers were relocated to land in the western United States, called Indian Territory. In a Congressional act of June 30, 1834, Indian Territory was described as “all that part of the United States west of the Mississippi, and not within the States of Missouri and Louisiana, or the Territory of Arkansas.”
In 1890, unassigned lands in the center of Indian Territory were organized as Oklahoma Territory. In 1906, Indian Territory and Oklahoma Territory were combined to form the state of Oklahoma, which was admitted into the union by Proclamation 780 on November 16, 1907. After that, Indian Territory no longer existed.