Conventional wisdom teaches that the Supreme Court's takings doctrine is a muddle. Appearances, however, are deceiving. The "property" protected by the Takings Clause is defined not by a single sovereign, but by the legislative enactments and judicial pronouncements of fifty separate states. As a result, federalism concerns - underappreciated in the takings literature - do and should play an important role in shaping the Court's takings doctrine. In particular, these concerns make it inappropriate for the Court to use the Takings Clause as a vehicle for articulating a comprehensive theory of the limits on government power to regulate land. This Article focuses on the ways in which federalism concerns (together with related institutional concerns) shape takings jurisprudence.