When Anna Katharina Elisabeth von der Leyen (1652-1738) married the margrave of Haraucourt in 1669, she became a member of one of the most ancient families of the duchy of Lorraine. As for all noblewomen of that time, this marriage would be the first step into a new life: Anna Katharina left the place where she had grown up, a tiny territory of the Holy Roman Empire, to join her husband in the German district of Lorraine – just across “the border” – where she would soon be exposed to war and officially become a subject of French King Louis XIV. Obviously, in order to fulfil expectations, Anna Katharina crossed both social and territorial borders. In Lorraine, she got strongly connected to a new family acting within a different aristocratic group and geographical, political and linguistic space. Did territorial borders matter to nobility before the rise of the nation-state? Or did noble families live a rather “borderless” life as by status and traditional habits, they travelled a lot more than the commonalty? The paper examines the von der Leyen, a rather overseen regional family of the Holy Roman Empire, by drawing special emphasis on their degree of cross-border activity towards Lorraine. On the basis of historical record drawn from the archives in Coblenz, I discuss the potential as well as the problems of a nobility-based analysis of early modern borders which includes a critical examination of the term “border region” for prenational contexts. The paper also explores recent attempts to historize borders in the early modern era which are strongly connected to the question of the actual practices of border crossing. In this regard, it argues for a small-scale analysis of “regional” families to get closer to the crossing and perceptions of early modern borders. The study also shows the importance of availability of historical record on which early modernists strongly depend as information on border perception is scarce in an era when national borders were yet to come.