Tsongmo Lake, also known as Tsomgo Lake or Changu Lake, is a glacial lake and is around 40 kms away from Gangtok. It is at an elevation of 3,753 m (12,313 ft). During the winter season the lake remains frozen. The lake surface reflects different colours with change of seasons. The colours of the lake also change with seasons. The lake is about 40 kilometres away from Gangtok on the Gangtok-Nathula Highway. A valid Permit issued by the Sikkim Police Department is required to visit the lake. The lake is oval in shape and is around 1 km in length and the width is around 500 mtrs.

The lake is the venue for the Guru Purnima festival which is also the Raksha Bandhan festival when the faith healers known as Jhakris of Sikkim assemble at the lake area to derive benefits from the healing qualities of the lake waters.