Hint to Timbo: Look up State Reservations on the BIA FAQ link

State Indian reservations, which are lands held in trust by a state for an Indian tribe. With state trust lands title is held by the state on behalf of the tribe and the lands are not subject to state property tax. They are subject to state law, however. State trust lands stem from treaties or other agreements between a tribal group and the state government or the colonial government(s) that preceded it.