This article examines the rise of borderland actors in Russia’s Orenburg province in the mid-eighteenth century. Established in the 1730s and the 1740s, the fortified line along the Iaik River became a hard border separating Russian-controlled Bashkiria and the Kazakh-Kalmyk steppes to the south. Using numerous case studies culled from the State Archive of the Orenburg Region, it considers the multi-national borderland communities (Tatar, Russian, Bashkir, Kalmyk, Kazakh, and Zunghar) that populated both sides of the Orenburg Line. Despite Russia’s attempts to control movement and monitor identities, border actors displayed considerable agency throughout this period, as their migrations, escapes, and crossings helped determine the transnational character of Russia’s southeastern region.