This article analyzes bottom-up institution-building processes in a region considered deforestation and environmental degradation hotspot. Utilizing the constitutionality approach developed by Haller, Acciaioli, and Rist (2016), we examine two recent cases of bottom-up institution-building in the department of Rivadavia, Chaco Salteño, Argentina. We highlight the similarities and differences between both constitutionality processes and identify various weaknesses in the two cases. We argue that constitutionality, understood as a process, has occurred to different (incomplete) degrees in each case. Finally, we show that external catalyzing agents play a decisive role in enabling or hampering the constitutionality process. Our study contributes to the literature on common-pool resource governance by highlighting how collective action can lead to participatory-development processes.