Tosar Lake is located at an altitude of 13000 ft in between the Mangan Ridge and the Chola Range. To the south east of the lake, is a giant cliff or mountain overlooking the Lake. It is considered sacred and worshiped by the local people. Some of the best views of the Khangchendzonga East face is seen from this region.

This trek begins from the road head at Naksuk, Naga Reserved Forest above Naga village which is about an hour drive from Mangan. It follows the old traditional yak and cow trails in the Reserve forest. It passes through soggy temperate  forest of broad leaved species and bamboos. This trek is especially popular for its mountain views, floral spectacle in summer, beautiful birds and views of pristine forest.    
Tosar Lake is located at the junction of the Mangan and Chola range. The maximum height of the ridge is about 4340 m at Maram Chu. The other important peaks of the Mangan ridge are Phyakchung (3740 m), Anden peak (3700 m) and Pandot peak (2375 m). The important spur is the Phodong spur running southwards from the main ridge. The southern face of the Mangan ridge is very steep whereas the north facing slope is gentler. The trek passes through the northern slope of the Mangan Ridge.

Important features along the trail
•    Water bodies - 2 perennial streams and 4 seasonal spring water.
•    View points/ Mountain views – Dzongu, Khangchendzonga mountain ranges and Teesta river.
•    Forest / vegetation Types – Maple, Chimal, Bamboo Groves, Temperate forest to Alpine vegetation as you ascend,
•    Animals / Birds – Butterfly, and other smaller birds.
•    Medicinal Plants / Flowers
•    Signage Along the trail – At diversion on Naga Gumpa and North Sikkim highway, Naga Gumpa (Trekking Take off Point), at Bojo Tar, Below Sohar Dhe.