Indian country is any of the many self-governing Native American communities throughout the United States. As a legal category, it includes "all land within the limits of any Indian reservation", "all dependent Indian communities within the borders of the United States", and "all Indian allotments, the Indian titles to which have not been extinguished." This legal classification defines American Indian tribal and individual land holdings as part of a reservation, an allotment, or a public domain allotment. All federal trust lands held for Native American tribes is Indian country. Federal, state, and local governments use this category in their legal processes.
This convention is followed generally in colloquial speech and is reflected in publications such as the Native American newspaper Indian Country Today
Related and historical meanings 
Historically, Indian country was considered the areas, regions, or territories beyond the frontier of settlement that were inhabited primarily by Native Americans. The first grants of land in what is now the United States made by the King of England left it to the grantee to make such arrangements as they were able with the Indians living on the granted land. As the original Thirteen Colonies grew and treaties were made, the de facto boundary between settled territory and Indian country during the 18th century was roughly the crest of the Appalachian Mountains, a boundary set into law by the Royal Proclamation of 1763, the Confederation Congress Proclamation of 1783, and later by the Nonintercourse Act. These areas were defined generally by boundaries set by treaties (or sometimes simply by political circumstances). It was understood that the law of the United States and the laws of individual states were unenforceable in Indian country (for all practical purposes), and tribes that lived on those lands had full sovereignty in those areas.
- N. Bruce Duthu, American Indians and the Law (NY: Penguin Library -Viking - 2008)
- David H. Getches, Charles F. Wilkinson, and Robert A. Williams, jr., Cases and Materials on Federal Indian Law, 4th Ed. (St. Paul: West Pub., 1998)
- Imre Sutton, ed., "The Political Geography of Indian Country." American Indian Culture and Research Journal, 15(02) 1991