The Congo Biogeochemical Observatory is an international consortium of researchers who study biogeochemical cycles (the pathways by which a key elements like carbon, nitrogen, and phosphorus move through the biotic and the abiotic compartments of Earth) in tropical Africa with focus on the Congo Basin. The Congo comprises the second largest swathe of tropical forest on Earth and faces mounting impacts from forest loss driven by shifting agriculture in concert with rapid human population growth. Given these accelerating impacts, we believe it is critical to study the biogeochemistry, ecology, and hydrology of this globally relevant yet largely understudied region.