Baseline morphometric information at a sub basin level is essential to develop an appropriate strategy for sustainable, socially acceptable, ecologically benign and economically viable development of a river basin. The present study was carried out in one of the less studied Thirumanimuttar river sub-basins of Cauvery river in the state of Tamilnadu, India. We used GIS and RS tools to study the morphometric characteristics of the basin. The seventh order main river is formed by several lower order streams forming a dentritic flow pattern. The mean bifurcation ratio is 3.61 indicating the basin is largely controlled by structure. The basin has medium drainage density of 0.996 per km2 and is elongated in shape. The length of overland flow values of the basin is 0.502, indicating high relief. The study has strengthened in understanding the hydrological, geological and geomorphological characteristics of the Thirumanimuttar drainage basin.