The Sikkimese often contend that North Sikkim is as beautiful as Switzerland. It’s not just a simple saying to lure the visitors but thousands have visited this place and many after them have also reiterated the fact that North Sikkim is indeed truly beautiful. Although much of North Sikkim can be toured with ease in the comforts of surface transportation, the remarkable Green Lake region offering a unique trekking experience does call for several days of rigorous walking with logistical support of a camping outfit
The journey to the North from Gangtok follows the North Sikkim Highway, an adventurous drive through high hills and deep river valleys that ultimately ends up in the foothills of the Himalayas where gentle meadows overlook snow-clad rocky mountains. The ever-changing views along the way include rustic wayside hamlets surrounded by terraced fields, monasteries, torrential mountain streams with lush green forests everywhere. The region of Yumthang, Yume Samdong, Gurudongmar, Chho Lhamu and Chopta Valley are the only part of North Sikkim that is accessible for tourists.
Mangan is the district headquarters located at an altitude of 3950 ft  and at a distance of 65 km from Gangtok. The road from Mangan goes straight to Chungthang and then  bifurcates on the left leading to the Lachen  Valley and the right going to the Lachung valley.  Lachen is the base from where tours to Thangu and Gurudongmar Lake are organized while Lachung on the other hand is the base for tours to Yumthang valley.