fgeo is a new R package for the analysis of ForestGEO data. The fgeo package includes code to access and manipulate datasets, and code to implement a wide range of analyses of plot species distributions, topography, demography, biomass, and species-habitat associations. fgeo includes a searchable list of functions, including help files with explanations and examples of all functions. The fgeo package builds on the original CTFS R package developed by Rick Condit and colleagues that is no longer maintained. Since fgeo is designed to be a dynamic tool, we welcome feedback, and are particularly interested in suggestions of new code that would be useful to the broader ForestGEO community.