The Mohegan Tribe is a federally recognized tribe and sovereign tribal nation of Mohegan people. Their reservation is the Mohegan Indian Reservation, located along the Thames River in present day Uncasville, Connecticut. The Mohegan tribe's independence as a sovereign nation has been documented by treaties and laws for over 350 years.  This first of such is the Treaty of Hartford.  This was secured by their Sachem (Chief) Uncas after his cooperation and victory with the English in the Pequot War from 1637 to 1638. Although the Treaty of Hartford established English recognition of the tribe's sovereignty in 1638, after the colonial period and loss of lands, the tribe struggled to maintain recognition of its identity. For many years, its people were assumed to have been assimilated into modern culture. The tribe was reorganized in the late 20th century and filed a federal land claims suit, seeking to regain land that the state of Connecticut had been illegally sold to the U.S. Federal Government. As part of the settlement, the Mohegan Nation gained federal recognition by the United States Government in 1994. That same year, the US Congress passed the Mohegan Nation (Connecticut) Land Claim Settlement Act. With this act, the federal government authorized the (recently cleaned-up) United Nuclear site for use as Mohegan reservation lands. The property was transferred to the United States in trust for the tribe shortly thereafter.