Fennoscandia was and still is one of the most mire-rich regions of the world calculated in relation to the land surface. 1 However, as a consequence of peatland drainages in the eighteenth, nineteenth, and twentieth centuries over 50, circa 30 and circa 25 percent, of the peatlands in natural condition in Finland, Sweden, and Norway respectively were damaged or destroyed. 2 Beginning in the nineteenth century, human-mire relationships were revalued and they continue to be subject to debate, new policies, and changing priorities. The goal of this article is to offer a historical explanation of why different types of peatlands became part of large-scale economic activities in Sweden and Finland 3 since the early eighteenth century. Particularly, this study seeks to disentangle how and on which basis different forms of land use were prioritized, how and why these practices changed, and how sciences and environmental knowledge promoted changes. The main research focus is on the developments in Sweden and Finland, although they are compared in relation to the countries from which they sought models and practices on the reclamation and utilization of bogs and mires.