This dataset is an inventory of reservoir details for the UK. It provides information, including reservoir location, type (impounding or non-impounding), use (water resources, hydro-electric, ecological, flood storage, canal), capacity, planning date, construction date, catchment National River Flow Archive (NRFA) gauge references and membership of a reservoir group, based on current usage within the CEH Monthly Hydrological Summary (https://nrfa.ceh.ac.uk/monthly-hydrological-summary-uk). The dataset comprises 273 individual reservoirs, which amount to approximately 90% of total UK reservoir storage. Data quality has been recorded, using a data flag system and a notes section, with references relevant to each reservoir provided.