The Rema-Kalenga wildlife sanctuary is a part of the
tarap hill reserved forest- the largest remnant of upland natural forest in the country. The sanctuary emcompasses several hills of different elevations and low laying valleys.
The hightest peak of the hills is about 67 meter from the sea level.
The sanctuary is drained by a number of small , sandy-bedded streams and includes one small (<0.5 ha) artificial lake. The forest is mixed evergreen, where tall trees are deciduous and the under storey evergreen.