The world faces a generic but critical challenge: how do we organize and conduct the very beginning and strategic stages of designing for longer-term changes in large, multi-system, multi-client and contentious contexts? Geodesign addresses this challenge. The International Geodesign Collaboration (IGC) was proposed by Carl Steinitz in 2015 and organized with Brian Orland and Tom Fisher in 2018. It now has more than 200 university teams which have completed 130 regional to local studies. All are in 2020-2035-2050 periods within climate and demographic-driven global assumptions, innovation-based scenarios, and all are in the same design language. Please see https://www.igc-geodesign.org/ and https://www.igc-geodesign.org/2019-20-projects in which all are assessed in the UN Sustainable Development Goals (SDGs). IGC is a volunteer organization with no budget, as every school is already (or should be) conducting such related work. IGC provides a way of sharing, comparing, and learning. We encourage all universities to join us, and invite practitioners to collaborate with us. Our presentation will describe the IGC and discuss implications of study area size, scale, complexity, and time on the organization of Geodesign. It will focus on the special aspects of organizing longer-term Geodesign studies for very large, multi-jurisdictional regions. The example will be the International Geodesign Collaborative SA Amazon 2050 Plan; a proof-of-concept study based on the UN Science Panel on the Amazon draft report “The Amazon We Want”.