Pergau Lake is located in the northwest of Kelantan, Batu Melintang, Jeli district. This reservoir located within latitudes of 5° 35' to5° 38' N and longitudes 101° 38' to 101° 41' E. The lake is about 130 km away from Kota Bharu and located about 30 km from Jeli town. The objective of the study is to determine the general geology of Pergau Lake and to produce also update the geological map of the study area. Moreover, petrography study of Pergau Lake was also done. The lake is a reservoir manmade lake made for the source of water to power the hydroelectric plant. Lithology of the study area was studied and is composed of granite. This granite is named as Noring Granite. It is a part of the Stong Complex which comprises three type of granite which is Berangkat Tonalite, Kenerong Microgranite and Noring Granite.In term of petrographic features, Noring Granite is composed of coarse-grained granite that showed distinct megacrystic pinkish alkali feldspar. Petrography study of Pergau Lake classified the granitic rock in study area as granite type of rock. It coarse grained in texture and contain phenocryst of alkali feldspar is a distinction and the granite is named biotite granite porphyry.