Recent research has shown the importance of studying military deployments and their effects on a wide range of social, political, and economic outcomes. In particular, it has demonstrated how the US has shaped the international system through the largest, and most enduring, military footprint in the twentieth and twenty-first centuries. However, data on US military deployments have been limited in scope and are often difficult to access, making it harder for researchers to use them more widely. In this article, we focus on three goals. First, we discuss the evolution of the quantitative US military deployment literature in recent years, highlighting some of the insights this work has generated for scholarship on international relations and US foreign policy. Second, we update the existing troop data assembled by Kane (2004) through 2020. We also include new data on deployment levels specific to US service branches. Third, to facilitate the use of these data we introduce troopdata, an R package containing the updated data and convenience functions to allow scholars to more easily access these data. [ABSTRACT FROM AUTHOR]