25 U.S.C. § 424 — Negotiations for cession of lands

The Secretary of the Interior may, at his own discretion, negotiate agreements with Indian tribes. He does this work through a United States Indian inspector. These agreements would give the United States portions of a tribe's reservation, or land that has already been divided among individual owners but is classified as surplus and unallotted. Any agreement reached this way does not become final on its own. It must first go to Congress, which has the power to ratify — or reject — it before it takes effect.