Arizona has more than 9 million surface acres of State Trust lands, interspersed throughout the state with federal and private lands. It represents approximately 13% of Arizona's total surface land ownership. Congress authorized conveyance of federal land grants to territories in the west at statehood to provide foundational support for basic public services, such as education and penitentiaries. Congress mandated that those lands be held in perpetual trust, and that standards for management and disposition of those lands would be codified within the states' constitution.