The 371 treaties between Indigenous nations and the United States were all promulgated during the first century of US existence. Congress halted formal treaty making in 1871, attaching a rider to the Indian Appropriation act of that year stipulating “that hereafter no Indian nation or tribe within the territory of the United States shall be acknowledged or recognized as an independent nation, tribe, or power with whom the United States may contract by treaty. Provided, further, that nothing herein contained shall be construed to invalidate or impair the obligation of any treaty heretofore lawfully made and ratified with any such Indian nation or tribe.” This measure meant that Congress and the president could now make laws affecting an Indigenous nation with or without negotiations or consent. Nevertheless, the provision reaffirmed the sovereign legal status of those Indigenous nations that had treaties. During the period of US–Indigenous treaty making, approximately two million square miles of land passed from Indigenous nations to the United States, some of it through treaty agreements and some through breach of standing treaties.

— An Indigenous Peoples' History of the United States (ReVisioning American History) by Roxanne Dunbar-Ortiz, Roxanne Dunbar Ortiz (Page 142)