Indian tribal land is generally exempt from local property taxes. However, when that land is leased to non-tribal parties, the lessee may be required to pay property tax based upon the value of the "possessory interest" that they have obtained under the lease. In 2013, the federal Bureau of Indian Affairs adopted regulations that many tribal advocates interpreted as prohibiting state and local governments from levying such "possessory interest" tax assessments.
However, the federal courts disagreed, and earlier this year, the Ninth Circuit issued an opinion in Agua Caliente Band v. Riverside County upholding these taxes. This represents a major victory for counties containing substantial tribal lands, who faced potentially significant revenue losses. The opinion was not published as formal precedent for subsequent cases; however, the views of the Ninth Circuit are nonetheless expected to be influential in any future disputes on this subject. The Agua Caliente tribe has until early June to request review by the U.S. Supreme Court.