Here is the petition in Penobscot Nation v. Frey:

Here is the petition in United States v. Frey:

Question presented (from the Penobscot petition):

Whether the Maine Indian Settlement Acts— consistent with this Court’s precedents on statutory interpretation and the Indian canons of construction— codify the historical understanding of the Penobscot Nation, the United States, and the State that the Penobscot Reservation encompasses the Main Stem of the Penobscot River.

Lower court materials here.

Update:

NCAI Amicus Brief

Members of Congress Amicus Brief

Maine State-Tribal Commission Amicus Brief