Human activity has replaced nature as the principal force shaping our planet. As a result, we stand at the dawn of a new geological epoch: the Anthropocene. Fundamental changes in American law will be required to mitigate and adapt to the negative environmental impacts produced in this new era. These changes will go far beyond the traditional scope of environmental law to encompass property law and other subjects. This Article analyzes how American property law should respond to the Anthropocene challenge. It demonstrates the need to transition from a property law system based on stability to a more dynamic system that accommodates large-scale environmental disruption. It argues that we must develop a new vision of ownership in which property rights are more flexible and less categorical than in the past, and that we must implement this transition in a manner that does not violate the Takings Clause. The Article proposes four overarching principles to guide the evolution of our property law system in the coming decades.