Several challenges abound with the accurate estimation of aquifer parameters in Groundwater resource development. This paper describes the investigation on the aquifer (mainly Ajali Sandstone Formation) parameters in Nsukka area. The Ajali Sandstone Formation is among the principal sources of groundwater in the area. (9) boreholes drilled in the area were analysed texturally using statistical grain size method.Results show that the highly permeable members of Ajali Sandstone are devoid of surface waters and are seen to be friable, medium-grained, poorly sorted, and highly cross-bedded. Recharge is mainly through rainfall. The distribution of major geological units, well log data, static water level data, and surface features were found to have influenced groundwater occurrence and flow pattern in the study area. The lithological logs showed sandy aquifers separated by clayey aquitards, while stratigraphic analyses of well lithological logs revealed the presence of at least four layers of contrasting hydraulic conductivity, making the aquiferous Ajali Sandstone homogenous and anisotropic. Values of permeability (k) from 0.00753 to 0.01512 cm 2 , hydraulic conductivity (K) from 8.2886 to 16.6444 m/s, transmissivity (T) between 455.87 and 1002.48m 2 s -1 , and specific yield from 2.35 to 4.76m 3 were found to be consistently high, thus suggesting thick and prolific aquiferous zones.