Although state and local governments only gradually assumed many of the functions we associate with a modern state, in the early U.S. West federal officials and troops worked to conquer territory; negotiate treaties; map, survey, and distribute land; establish and enforce laws; and administer Indian agencies and territorial governments. However, an active federal government was not necessarily a powerful one. Even as the federal government claimed dominion over great expanses and diverse and dispersed populations in western North America, it faced fundamental challenges to sovereignty, including the inability to fulfill treaty obligations; the failure to enforce laws or to maintain a monopoly on violence; and the lack of territorial control over large parts of the country. These problems were compounded by corrupt and incompetent officials and by the government's dependence on local agents who had questionable loyalties. These struggles remind us that the antebellum West was both the region where the federal government was most active and where the limitations of federal power were most evident. Thinking about state power in the West changes the calculus by which we discuss the relative strength or weakness of the state in the early republic. It forces us to consider not just the form and extent of state authority but also whether federal agents achieved the goals and responsibilities they set out for themselves.