The territoriality-deterritoriality dichotomy is a central axis of contemporary political imagination. The way in which relations and proportions vary and move along this axis indicates the identity and political dynamics of modernity. In this chapter, these dynamics are considered from the perspective of environmentalism. The chapter considers territoriality as a reflection of power relations and the construction of unified identities that correspond to the monopoly on political geography. Deterritorialization is the result of economic and cultural globalization that has opened up territory for interaction between diverse social agents. These processes have been promoted by supranational and regional entities that have brought to the surface repressed multidimensional, multiloyal regional subjects, but have also created a sense of cosmopolitanism and cosmopolitan identities. This was also the case with environmentalism, for which nation-states were too large and cumbersome to deal with specific environmental issues at the micro level, but too small and insufficient to deal with global environmental challenges. Hence, environmentalists developed the concepts of bioregionalism and environmental citizenship in their political philosophy, policies, and activist efforts, which this chapter analyzes in detail.