Numerous Supreme Court decisions have created important precedents in Indian country jurisdiction, such as Worcester v. Georgia, Oliphant v. Suquamish Tribe, Montana v. United States, and McGirt v. Oklahoma.

[2] At this time, states wanted to remove Indians from their territory, which led to more treaties and the establishment of the controversial policy of U.S. ethnic cleansing.

It was the Indian Removal Act that helped Jackson set into place the Trail of Tears in 1831.

[7] Very soon after many of the Indians losing the land which they earned through the Dawes Act, white settlers moved in on these open lots.

This created a checkerboard effect, and made it nearly impossible to have sizable gains in farming and grazing.

During the Allotment Act, the Native American population reached its lowest point in history.

[10] The Allotment period was coming to a close in 1924 when Congress passed a statute granting citizenship to all Indians born within the United States.

The Meriam Report documented the utter failure of the Dawes Act and the allotment policy.

It sought to protect the tribes and allow them to establish the legal structures for their own self-governments.

[12] The tribes were now authorized to create their own constitutions and laws, which could be ratified by a vote among the tribal members.

After decades of misfortune and loss of culture and property, the Indian Reorganization Act put a stop to the destruction of the tribes.

[13] Unclear jurisdictional boundaries between states and tribes prompted the beginning of the Indian termination policy era.

[14] The termination era began when Congress passed House Concurrent Resolution 108 in 1953, which stated: Whereas it is the policy of Congress, as rapidly as possible, to make the Indians within the territorial limits of the United States subject to the same laws and entitled to the same privileges and responsibilities as are applicable to other citizens of the United States, to end their status as wards of the United States, and to grant them all the rights and prerogatives pertaining to American citizenship....[15]The policy of termination has been seen as a direct attack on the sovereignty of Indian nations - without being considered a reservation or a nation, Indian tribes lost jurisdiction, taxation protection, and emerged into a different world.

In the twelve years of this policy, 109 tribes were terminated, with severe effects on education, health care, and economic stability.

[17] Termination might have been seen as a method of "freeing" tribes from the BIA and other governmental programs, but the policy likely hindered the efforts of Native Americans for tribal self-rule.

Presidents Lyndon B. Johnson and Richard Nixon would lead the nation away from termination into self-determination.

The legislation that has arisen from this policy of self-determination, which has been in effect since the late 1960s to the present day, has greatly influenced modern-day Indian country jurisdiction.

[citation needed] For example, when the Devils Lake Sioux litigated the question of tribal authority against the North Dakota Public Service Commission, which was operating within reservation borders, the court, relying in part on interpretations of 'Indian Character', ruled that the tribe had no authority over privately held lands even though more Indians than non-Indians lived on the reservation, yet more acreage was held in non-Indian ownership.

All of the political and legal interpretations of this situation may not eliminate the meaning of Indian Country, but as such they obscure the increasing diminishment of tribal sovereignty within reservation borders.

[29] In 2020, the United States Supreme Court ruled in McGirt v. Oklahoma that the tribal statistical area (and former reservation) of the Muscogee (Creek) Nation remains under the tribal sovereignty of the Muscogee (Creek) Nation for the purposes of the Major Crimes Act.

[32] Federal courts have no jurisdiction in civil cases involving divorce, adoption, child custody, or probate.

Jurisdiction is also granted, though not exclusively, to tribal courts over non-major crimes by Indians against non-Indians.

[42] In matters involving adoption and child custody proceeding between parents, the division of jurisdiction is very similar.