This dissertation considers how the Californias have inherited two different colonial histories and how these different histories influence representations of environmental and social problems in the U.S.-Mexico borderlands. I argue that contradictory demands placed on the contemporary inhabitants and environments of the U.S.-Mexico border region today are characteristic of a long history of conflicted representations of the area. Regional boundaries in the Southwestern United States and Northern Mexico have been articulated by characterizing landscapes as both paradisical and uninhabitable. These attributions of degrees of habitability allow for colonial and settler colonial understandings of human difference, in terms of both gender and race, to borrow a sense of reality from topographic and climatological features. Focusing on women writers who understand the subsumption of the region under the nation to be analogous to the subsumption of gender difference under patriarchy, this dissertation begins from a consideration of transnational feminism in order to stage critical comparisons of contemporary literature and artwork produced in the geographical (and sometimes cultural) margins of two countries. This comparison requires working across and between disciplinary fields, including Mexican Literary Studies, Latinx Studies, Border Studies, American Studies, Environmental Literary Studies. The deserts of the Southwestern United States and the Baja Californian peninsula have been represented in literature from the U.S. and Mexico as sites of potential transnational friendship and of ongoing political violence, of environmental pressures depicted as both idyllic and unrelenting. I argue that in the border region writers are called on to perform a relationship to local environmental conditions in order to bridge and translate realities. My dissertation places this ambivalence within a longer genealogy of Latin American thought and overlapping histories of colonization and colonialism, which pre-exist and underpin debates about postmodernity and border culture. From this longer perspective we learn that there are physical, linguistic and ethical obstacles to this imagined work of mediation. Contemporary writers like Aglae Margalli, Regina Swain, Rosario Sanmiguel and Gayl Jones understand the demand to represent particular relationships between local and national culture as a rehearsal of gendered and racial panic over imagined threats of popular culture, tourism, urbanization, and migration at the border. Reading their focus on the difficulty of moving between languages, landscapes, and climates as resistance to external demands for regional self-representation, I argue that the State’s violent deployment of fantasies of the border region finds its critical analysis in literature that remains regional, without satisfying dominant fantasies about the limits and margins of national cultures. My framing of the relationship between Alta and Baja California as a problem relieves the pressure to read border writers in terms of their success as cultural intermediaries. In this way, regional histories and landscapes provide alternative figures for and articulations of limitation, transition, and transgression.