This is the Shared Aquifer Diagnostic Analysis (SADA) report for the Gedaref- Adigrat groundwater basin shared between Sudan and Ethiopia. The report serves as a baseline fact-based representation of the current status of the aquifer including its geologic and hydro-geologic characteristics, groundwater availability and use, surface-groundwater interaction, socio-economic aspects, groundwater governance and policies, groundwater management challenges, climate change impacts and trans-boundary threats, as well as identification of key gaps and threats to the management of groundwater resources. The study was largely a review of secondary existing/archived historical datasets and information with limited primary field data collection involving both technical and social science approaches. The collected data was harmonized to characterize the aquifer across the two-shared countries for information management. The technical data gathering methodology included a review of datasets and previous works and information to characterize the physical aspects of the aquifer including areal extent and architecture, hydraulic properties and storage, physiography, climate, vegetation, soils and geology. Social sciences methodology included, in-depth interviews; focus group discussions; field observation; key stakeholder mapping; reviews of reports, manuscripts and official documentation.