DOE’s Geothermal Technologies Office (GTO) tasked STPI with developing a roadmap of research and development (R&D) activities that are appropriate for the 5-year operation of the Frontier Observatory for Research in Geothermal Energy (FORGE) initiative and, if successfully executed, can address larger technical challenges facing enhanced geothermal systems. The FORGE Roadmap incorporates feedback and input received during STPI’s elicitation process, which included a literature review, interviews with subject matter experts, and a facilitated workshop with the research community in August 2018. In addition, this document is inclusive of feedback received from DOE on the three previous drafts as well as the feedback received as part of the peer review process.