"... Duluth, Minnesota, where in 1985 the secretary of the Interior used section 5 of the IRA to transform the land under a boarded-up Sears & Roebuck Co. store downtown into an Indian reservation ..."  Feds. can do that unilaterally on federal lands, but must negotiate with the state, if it is state land.  Usually there is an exchange of lands of equal value between the Fed. and State.