Talk of an “American Empire” has long been considered anathema in US political circles and the wider public. It seemed misguided, perverse even in the light of the country’s identity as an exporter of freedom and opportunity. However, building, keeping, and adjusting empire was the norm in US history, not the exception. This lecture will provide a broad overview of these processes, paying attention to the architects and beneficiaries of US empire as well as to its subjects and victims. It will start with revolutionary-era articulations of an “empire of liberty” and work its way through the nation’s westward expansion in the 19th century; the acquisition of overseas colonies after 1898; the birth of an “American Century”; the global network of US military bases established during the Cold War; and the 21st-century war on terror and its ramifications. While deflating the myth of American exceptionalism, imperial histories of the United States have also addressed the question of what made US manifestations of imperial power specific, with varying results. Such issues of comparison are important and will be raised in the lecture to the extent possible.