Indian Territory comprises a portion of the region originally set apart by the United States government as a home for Indian tribes. It is bounded N. by Kansas, from which it is separated by the parallel 37° N., E. by Missouri and Arkansas, S. by Texas, from which it is separated by the Red River, and W. by Oklahoma Territory. The line dividing these two territories is exceedingly irregular, and Oklahoma lies both W. and N. of Indian Territory. Beginning at the N. this boundary is formed by the meridian 96° W., the parallel 36° 10' N., and the meridian 96° 37' 30" W. to the N. Fork of the Canadian River. S. and W. of this stream the line is continued by the meridian 96° 47' W. to the Canadian River, by that river to the meridian 98° W., and thence S. to the Red River. The section of land situated S. of Kansas and E. of Texas and the Public Land Strip, known as the Cherokee Outlet, is also described as a part of Indian Territory, although it is under the jurisdiction of Oklahoma (q.v.), of which it will ultimately become a part. The area, not including the Cherokee Outlet, is 31,000 sq. m.
The surface of the territory consists mainly of rolling prairie land rising gradually from the south-east toward the N. and W. In the south-east the surface is broken by low ranges of the Ozark Mountains which cross the Arkansas border. The most important groups are the San Bois and Shawnee. In the south-west are the Arbuckle Mountains. The mineral resources are practically undeveloped, but coal, copper, iron, marble, and building stones are known to exist in considerable quantities. The territory is well watered, and is drained by the Red and Arkansas Rivers and their numerous tributaries. The river bottoms are wide and fertile, subject to overflow in the spring, and usually enclosed between bluffs which rise abruptly to the intervening uplands. The north-eastern part is well wooded, and a belt of forest, known as the 'Cross-timbers,' extends from the Arkansas River to the
Brazos in Texas. The black bear, brown bear, antelope, and deer are abundant; wild turkeys, prairie-hens, and sage-hens also abound.
Indian Territory when first established included all the hitherto unorganised portion of the Louisiana Purchase, and was designed for occupancy by the tribes then east of the Mississippi. During the years 1833 and 1834 the Creeks, Choctaws, Chickasaws, and Cherokees were removed to their new home. In 1838 the Seminoles were added, and the remnants of several other tribes followed shortly after. Treaties were made by the government, covenanting to maintain the title of the country to the Indian tribes. The original grants extended northward from the Red River, including portions of what are now Kansas and Nebraska, and westward to the 100th meridian. By subsequent treaties with the Indians, the United States acquired control of the country N. of parallel 37°. A strip of land between the parallels 36° 30' N. and 37° N., and between the meridians 100° W. and 103° W., later known as the Public Land Strip, was, after the annexation of Texas, for a time erroneously reckoned as a part of Indian Territory.
In 1866 the United States purchased the western portion of the various grants to be allotted to other Indian tribes or to freedmen. At the same time, the Seminoles, who had parted with their entire domain, purchased a portion of the land ceded by the Creeks. Tribes whose homes were west of the Mississippi have at various times been settled on these lands. By consent of the Indians, part of these lands were in 1889 and 1890 thrown open to white settlers, and the organisation of Oklahoma reduced Indian Territory to its present limits.
The Cherokees, Choctaws, Creeks, Chickasaws, Seminoles, and some of the smaller tribes at or near the Quapaw Agency in the north-east have made considerable progress in civilisation. Schools and churches have been established. There are excellent farms and cattle ranges, and commerce has gained some foothold. The Missouri, Kansas, and Texas Railway crosses the territory from N. to S. Before the civil war the Indians owned negro slaves, and during the war some of the civilised tribes sided with the South, and for a time were considered to have forfeited their lands. The territory comprises three divisions, partly under the jurisdiction of United States courts and partly under tribal jurisdiction. The judicial centre of the first district is at the Quapaw Agency, of the second at McAlistor, and of the third at Ardmore.
Population at the census of 1890, 186,490, of whom 177,682 are members of the five civilised tribes (with descendants of former negro slaves), and the remainder are Indians on reservations. See the articles AMERICAN INDIANS, OKLAHOMA, CHEROKEES, &c.