Indian Country was originally
designated in 1793 under the King's
Proclamation Line.
The boundaries moved west of the
Mississippi under the
Indian Trade and Intercourse Act of
1834.
By 1876, with the admission of
Kansas and Nebraska to the Union,
Indian Country had shrunk to what is
now the state of Oklahoma, excluding
the panhandle.
By 1889 after the passage and
initial implementation of General
Allotment Act and the creation of
Oklahoma Territory, Indian Country
had shrunk to its final form.