The article considers the importance of frontier studies in historical archaeology and discusses applicability of some of the concepts deriving from postcolonial theories for a better understanding of human relationships in the frontier zones. The conditions of frontiers and borderlands are compared with the characteristics of the "Third Space" described by Homi Bhabha as a realm of negotiation, translation and remaking. It is argued that concepts developed in postcolonial theories, such as "Third Space," "in-betweeness" or hybridity, are useful not only to address cultural and social processes in borderlands that were created by colonial empires. They are also an apt way to conceptualize relationships in frontiers that lacked colonial stigma. To illustrate this point, two different historical examples of borderlands are scrutinized in this paper: the medieval frontier region that emerged between Denmark and the Northwestern Slavic area and the creation of the colonial frontier in Northeastern America through the establishment of the Praying Indian Towns.