Within the space of a battle to halt ski resort expansion and snowmaking on the San Francisco Peaks, a mountain in northern Arizona, a coalition has emerged of indigenous activists (primarily Diné), Euroamerican environmentalists, and anarchists. The resulting collaboration, Mountain Defense, goes beyond usual models of environmentalist-indigenous alliances as temporary and incommensurate. This dissertation explores the development of the Mountain Defense movement over time, the motivations of activists from divergent backgrounds in opposing snowmaking, the social interactions and negotiations of identity within this group, and the public discourse by which they construct a message about this space and threats to it. Ethnographic fieldwork was undertaken from 2009 to 2015; key methods of data collection included participant observation, interviews, archival research, and collection of spoken, print, and online communication. This data was analyzed for emergent themes as well as the ways in which meaning was produced between parties. Situating Mountain Defense within scholarship on place-making, traditional ecological knowledge (TEK), and social constructionism, this dissertation explicates how the movement has articulated a hybrid knowledge, including layered conceptualizations of sacred land and syntheses of sacred and scientific idioms in expressing the dangers of snowmaking technology. This research also speaks to the complex dimensions and continuing salience of Diné relationships with the San Francisco Peaks and the ways in which snowmaking and expansion threaten these.