Geological model is part of groundwater modelling processes. 3D geological models such as GSI3D and GOCAD are used extensively for modelling subsurface geology. These models require multiple input datasets from boreholes, geology maps, and geophysical data. However, due to insufficient definitive data, widely spaced data points that are interpolated were usually used for representation of a geological unit. Since the requirement of extensive data is always the main issue, a geological model is only applied for an area with sufficient data. In this study, minimal and accessible spatial datasets were used in the model for representation of the geological unit. These datasets were chosen to allow the model to be applied in areas of limited datasets. Via the GIS platform, the methodology was developed for the representation of geology in particular the aquifer unit. The raster surface of the geological layer was created in GIS using the information of dip, strike and faults displacement taken from the geological map. The developed GIS based geological model is capable of viewing a geological cross section, modelling the thickness and outcrop boundary of an aquifer unit. The model was tested by reconstruction of the geology map for the Slea catchment, in the United Kingdom and prediction of the thickness of the Lincolnshire Limestone aquifer.