This study characterize groundwater yield and flow pattern on a shallow overburden aquifers of a basement complex rock in Ilara-mokin and its’ environs, southwestern Nigeria. A total of 40 wells were sampled by using a handheld GPS and well estimator to collect data on the wells parameters and the physiographic characteristics of the well’s locations. The data collected include: elevation, longitude, latitude, well depth, depth to water and well diameter of the sampled wells. The mean yield of the well has revealed by this study is 1.21m 3 , with high variability in yield depending on the nature of the underlying overburden aquifers of the sampled well. The static water level, groundwater flow direction, surface profile and 3-D elevation model of the study area were produced from the data collected using ArcGis 9.3 and surfer 8 GIS software. The groundwater flow direction in the study is towards the southwestern part of the study area with few exceptions as the case of Ikota in the eastern part of the study area. The study concluded that Ilara-mokin and it’s’ environs have poor groundwater yield that can sustain the increasing population. It is therefore recommended that there should be proper development, management and advance exploration of the groundwater in areas where water level is close to the surface especially within the lowland areas and isolated marginally thick overburden as confirmed by a previous hydro-geophysical studies carried out in the area. Keywords : Groundwater Flow, Yield, Overburden, Shallow Aquifer, Characterization, Static Water Level.
