Gridded hydrological model river flow estimates on a 1km grid over Northern Ireland for the period Dec 1980 - Nov 2011. The dataset includes monthly mean river flow, annual maxima of daily mean river flow (water years Oct - Sept) and annual minima of 7-day mean river flow (years spanning Dec-Nov) (units: m3/s). The data are provided in gridded netCDF files. There is one file for each variable. To aid interpretation, three additional spatial datasets are provided: a) digitally-derived catchment areas and b) estimated locations of flow gauging stations both on the 1km x 1km grid and c) a 1km x 1km grid identifying majority lake cells. The data were produced as part of UK-SCAPE (UK Status, Change And Projections of the Environment, Work Package 2: Case Study - Water) a NERC-funded National Capability Science Single Centre award.