The Cerrado - the second largest Brazilian biome - faces an intense expansion of grain monocultures (soy) and livestock, being considered the world’s newest agricultural frontier. The region of Matopiba - a part of the Cerrado located in the states of Maranhão, Tocantins, Piauí and Bahia - is experiencing the most recent expansion of the agricultural frontier. While often framed as an ‘empty space’, this region is home to a diversity of traditional communities, territories and environmentally protected areas. This article analyzes the expansion of agrarian extractivism and its consequent socio-environmental conflicts in the Cerrado regions of Matopiba, especially surrounding the National Park of Nascentes do Rio Parnaíba, an environmentally protected area inhabited by several traditional communities facing threats and challenges resulting from the expansion of soy production in the region. These traditional communities suffer the effects of this expansion in multiple ways, including the loss of territories (land is their source of life, production and identity), deforestation and water scarcity.