Lachen is a high altitude town in North Sikkim. It is located at an elevation of 9100 ft above MSL. The word Lachen means “big pass”. The town is being promoted as a tourist destination by the Sikkimese government. The town forms the base to The Chopta Valley and Gurudongmar Lake (17,300 ft). An annual Yak race, The Thangu is held here in summer.

Lachen is about 129 km from Gangtok and can be reached via a six-hour road journey. A short two-day-long trekking route also connects Yumthang Valley to Lachen. It has a population of around 1000. Lachen has its own system of rules and regulations called Dzumsa. The heads of the Dzumsa are known as Pipon & Gyenbos.

To the north, there is the old town of Thangu. In Thangu, the daytime temperature varies from 4 to 10 degrees even in the months of June and July. Gurudongmar Lake (17,300 ft) can be reached from Lachen, a sacred lake in the Great Himalayas Region.

The best time to visit Lachen is from October to June.