This research examines the political character of nature conservation territorialization in Patagonia-Ays & eacute;n, focusing on the creation of Cerro Castillo National Park (PNCC) as a key case in the consolidation of the La Ruta de los Parques de la Patagonia conservationist megaproject. Through semi-structured interviews with key actors and field observation, the local implications of the conservationist turn in Cerro Castillo are explored. The results highlight two dimensions: first, the creation of the PNCC, driven by a public-private agreement, is based on an ecological sustainability rationale that conditions the historical forms of relationship between local communities and nature, generating tensions and controversies; second, the conditioning of the territory through the deployment of local development strategies, specifically based on local training in tourism, and reactive governance facilitates the local implementation of the sustainability agenda. It is concluded that the processes of conservation territorialization can help to understand how sustainability narratives materialized in local territories, modifying the way territories are produced and understood.