The digital exhibit will provide details on a draft ISG that extends the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) to subsurface residual radioactivity. The multi-federal-agency MARSSIM guidance document is used worldwide to plan radiological surveys, but it is only applicable to surveys of soil and building surfaces. The draft ISG was published for comment in October 2023 and will address radiological surveys for open surfaces in the subsurface including open excavations, building substructures, and backfill or reuse materials. The draft ISG also addresses assessment of risk from existing groundwater contamination and submerged sources. Lessons learned and experience from review of decommissioning plans for complex materials sites and license termination plans for reactor decommissioning are incorporated into the ISG. The ISG is expected to increase transparency and efficiency in the license termination process.