Abstract: The study area Eiyenkorin and its environs fall within the Precambrian Basement Complex of Southwestern Nigeria. This research was aimed at geological mapping and studying of the different rock units in the area to decipher their structural relationships and established their lithologic boundaries. Geological field mapping and identification of associated structural elements such as strikes of foliations and dips, azimuths of folds and joints and orientations of dykes were measured using a compass.