This article describes how Nuevomexicanas/os have used texts, images, and other media to reclaim the lands they lost in the US-Mexico War. Along the way, it models a method for reading “imagined environments”—the frameworks through which human groups have represented, related to, and resided in their more-than-human worlds. This article focuses on two generations of writer-activists. In the 1930s, 1940s, and 1950s, Adelina Otero-Warren and Fabiola Cabeza de Baca situated themselves in the Precarious Desert, an imagined environment of constraints, contingencies, and struggles for survival. Then, in the 1960s and 1970s, the Alianza Federal de Mercedes revived the Pueblo Olvidado, an imagined environment saturated with laws, treaties, and cultural traditions. Despite many differences, both generations shared a desire to settle on and profit from Native lands. But though they never became environmentalists, they experimented with environmental writing and politics. By recovering these experiments, this article shows how media produce—rather than simply portray—lands and waters. Ultimately it tells the story of the borderlands as a series of struggles over what environments are, whom they can contain, and how they should be used.