Statutes at Large, 23:385)[1] is a law passed by the United States Congress in 1885 as the final section of the Indian Appropriations Act of that year.

The Major Crimes Act was passed by Congress in response to the Supreme Court of the United States's ruling in Ex parte Crow Dog (109 U.S. 556 (1883)) that overturned the federal court conviction of Brule Lakota sub-chief Crow Dog for the murder of principal chief Spotted Tail on the Rosebud Indian Reservation.

That immediately upon and after the date of the passage of this act, all Indians committing against the person or property of another Indian or other person any of the following crimes, namely, murder, manslaughter, rape, assault with intent to kill, arson, burglary, and larceny, within any territory of the United States, and either within or without the Indian reservation, shall be subject therefor to the laws of said territory relating to said crimes, and shall be tried therefor in the same courts, and in the same manner, and shall be subject to the same penalties, as are all other persons charged with the commission of the said crimes respectively; and said courts are hereby given jurisdiction in all such cases; and all such Indians committing any of the above-described crimes against the person or property of another Indian or other person, within the boundaries of any State of the United States, and within the limits of any Indian reservation, shall be subject to the same laws, tried in the same courts, and in the same manner, and subject to the same penalties, as are all other persons committing any of the above crimes within the exclusive jurisdiction of the United States.This list of crimes has since been updated to the following (as of Pub.

While the Court agreed that the prosecution of major crimes did not fall within Congress's power to regulate commerce with the Indian tribes, it ruled that the trust relationship between the federal government and the tribes conferred on Congress both the duty and the power to regulate tribal affairs.

[5] The Major Crimes Act was the focal point of the Supreme Court case McGirt v. Oklahoma, 591 U.S. ___ (2020), which found that nearly half of the state of Oklahoma had not been disestablished as a Native American reservation by Congress prior to Oklahoma's statehood and thus remained Indian country, such that crimes committed by enrolled tribal members cannot be tried in state court.