Kallar is a scenic location situated on the way to Ponmudi from Thiruvananthapuram city and is located on the banks of the Vamanapuram River, a tributary of Neyyar River. The river at Kallar has many attractive, round-shaped boulders and brightly-coloured pebbles, especially in the upper reaches of its course. A trek to Meenmutty Waterfalls in Kallar is among the most famous trails in the area.