This research explores the vernacular architecture of the Choapa Valley, an oasis located in a semi-desert region of northern Chile known as "Norte chico" ["Little north"], which has the particularity of being the narrowest part of Chile. Here the traditional architecture is a product of both the adaptation to different environments and the syncretism between indigenous traditions and the Hispanic legacy. Although this area has been little studied, it is an important vernacular heritage that provides lessons for environment, society and economy through simple design solutions. The architecture throughout the Choapa Valley was documented through field analysis in order to define its main features and to explore aspects of sustainability. This research confirms that the practice of vernacular architecture is an ongoing tradition constantly readapted to satisfy new needs, being a living reference for contemporary architecture.