Sioux descendants have filed a lawsuit against the United States for federal recognition of their tribe, and for monetary damages over land that their attorney said was fraudulently dispossessed. 

Tom Smith, a Mdewakanton Dakota lineal descendant, said on Indigenous Peoples' Day that the lawsuit asks for the Sioux half-breed tribe and its lineal descendants to be federally recognized.

"This federal recognition will restore and preserve the Dakota identity of which these lineal descendants have been long deprived," Smith said.

Attorney Erick Kaardal, who is representing the group filing the lawsuit, said they're also asking for monetary damages over 500 square miles of land, once known as the Lake Pepin Reservation, which he said was seized through deception, manipulation and fraud.

The Minnesota Historical Society said the 1830 Treaty of Prairie du Chien set aside 320,000 acres of potentially valuable land west of Lake Pepin for the descendants. Kaardal mentioned two instances where the U.S. unsuccessfully tried to buy that land.

Federal officials in 1849 sent representatives to negotiate with the Sioux descendants to purchase the reservation, according to Kaardal. The U.S. and descendants agreed to a treaty where federal officials would buy the land from the descendants for $200,000.

"The U.S. Senate did not ratify the treaty because it was too expensive," Kaardal said. 

The U.S. and Dakota nation signed two land sale agreements in 1851 that gave the federal government control of "most of the future southern Minnesota," according to the historical society. 

"That was agreed to with a provision for Lake Pepin Reservation, where the United States would pay $150,000 for the Lake Pepin Reservation," Kaardal said. 

The 1851 agreements were approved by the U.S. Senate, though the provision was taken out since the Sioux descendants had not been consulted.

According to Kaardal, a commissioner for the U.S. Department of the Interior in 1970 wrote a letter to Minnesota's General Land Office 19 years later that validated patents, which doesn't show the Indian land title set in the 1830 treaty.  

The lawsuit, which Kaardal said was filed in the U.S. Court of Federal Claims, is asking for at least $5 billion in monetary damages. 

WCCO has reached out to the U.S. Bureau of Indian Affairs and the Bureau of Indian Education for comment. The Bureau of Land Management said it doesn't comment on pending litigation.