Kyongnosla Alpine Sanctuary is a nature reserve in Gangtok district, Sikkim, India. It is situated around the area adjoining the Tsomgo (Changu) lake along the Nathula Road. Located about 31 km east of Gangtok, the capital of Sikkim, this sanctuary covers an area of about 31 km2, and extends from the "15th Mile" police check point up to and along the ridges bordering the Rong Chu Valley and Lake Tsomgo. Rich in both flora and fauna, rare, endangered ground orchids and rhododendrons interspersed among tall junipers and taller silver firs are among the important plants present. Rhododendron niveum (the State Tree of Sikkim) and Cypripedium tibeticum (the ground slipper orchid), which is on the verge of extinction, have also been introduced here. Kyongnosla Alpine Sanctuary is part of the Sacred Himalayan Landscape. The best time to visit the sanctuary is in May, June, October and November, when the climate is pleasant, dry and warm.