Dear Mr. Lariccia,
Thank you for posting your request on History Hub!
In 1871, the Congress passed legislation stating tribal nations would no longer be recognized as sovereign nations that a treaty could be made with. The tribes that signed up through 1868 would be still recognized but from 1871 onward, relations with tribal nations would be conducted via legislation and executive orders. This ended the treaty-era and began the start of the assimilation-era. For such laws and executive orders following 1870, please contact the Center for Legislative Archives at firstname.lastname@example.org.
For more general information about treaties with Native American tribes and the United States, please view NARA’s web pages at https://www.archives.gov/research/native-americans/treaties.
We hope this is helpful. Best of luck with your research!
[Information provided by Cody White, Subject Matter Expert]