Dzongu is a triangular region in North Sikkim opposite to Mangan. It is bounded by the Teesta River in the south-east, Tholung Chu River in the north-east and by mighty mountains in the west. It borders the Kanchenjunga Biosphere Reserve. Dzongu has been established as an official reserve for the Lepcha people, the aboriginal inhabitants of Sikkim. The Lepchas have strong ties with the nature and have lived here for centuries. An understanding of their culture, customs and language helps to foster an appreciation of the beautiful mountains, deep forests, and the emerald-colored Teesta River.
The region receives few tourists hence seems almost untouched. It is sparsely populated and most of it is covered with dense vegetation. Rice fields and Cardamom plantations can be seen near the villages. The whole area is divided into upper and lower Dzongu. Some adventurous treks can be arranged from Dzongu towards Green Lake area via Kyishongla pass. Most of Dzongu region is still unexplored because of its inaccessibility and the forests in these area has a rich diversity. There is an ecotourism initiative in Dzongu which offers simple homestays in ethnic Lepcha village.