Political states claim the moral right to rule the persons living within their jurisdiction; they claim the authority to make and enforce laws, establish policies, and allocate benefits and burdens of various kinds. But states also claim rights over their territories. These include rights to establish and protect borders, to control airspace, extract and use natural resources on and beneath their geographical region. Philosophers have long wondered about the basis for states claims to authority over persons. But there are additional questions regarding the territorial authority claimed by states. How do states come to possess rights to the natural resources that lie beneath the ground? How might the moral character of the initial acquisition of land impact a states present claims to authority? In Boundaries of Authority (Oxford University Press, 2016) A. John Simmons (University of Virginia) argues that leading accounts of state authority are insufficient to address successfully the distinctive questions regarding state boundaries. Building on his own Lockean individualist account of authority, Simmons develops a philosophical conception of how the moral rights claimed by states could be justified.