Lachen is a town in North Sikkim district in the Indian state of Sikkim. It is located at an elevation of 2,750 metres. The name 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. An annual yak race, the Thangu is held here in summer. Lachen is about 129 kilometres (80 mi) from the capital Gangtok, and can be reached via a six-hour road journey. A short two-day-long trekking route also connects the Yumthang Valley to Lachen. It has a population of around 1,000. Lachen has its own system of rules and regulations known as Dzumsa. The heads of the Dzumsa are known as Pipon and Gyenbos. To the north there is the old town of Thangu where the daytime temperature varies from 4 to 12 degrees Celsius (40 to 55 °F), even in the months of June and July. Gurudongmar Lake can be reached from Lachen, a sacred lake in the Great Himalayas Region.