The tribe was federally recognized in 1983 through the Mashantucket Pequot Land Claims Settlement Act. The federal land claims suit was brought by the tribe against the State of Connecticut and the Federal government, charging that the tribe had been illegally deprived of its land through state actions that were not ratified by the Senate. As part of the settlement of this suit, Congress gave federal recognition to the tribe, in addition to approving financial compensation so that the tribe could repurchase lost land. Tribal membership is based on proven lineal descent of 11 Pequot families whose ancestors were listed in the 1900 US Census.