Panggong-tso, which means 'the long, narrow enchanting lake' in Tibetan, is located about 8km of Rutok Xian which is 132km form Ali. It is also known as the 'swan lake' of the border (it is the place where China borders the Indian Kashmir).

It has an altitude of 4,241m, with a total length of 150 km from west to east and it is narrower from south to north, with the narrowest point being 40 meters. Approximately the lake has an area of 604 sq. km. The deepest point of the lake is 41.3 meters. The eastern part of the lake belongs to China, while the western part belongs to Indian Kashmir. Ice period of the lake is 6 months every year.

The Birds' Islet is located in the lake, where thousands of gulls inhabit. The islet is small, about 300 meters in length and 200 meters in width, with red willows clustering along the lake bank, forming a beautiful view.

Gulls and their eggs can be seen everywhere, between rocks, in the grass, on the lake, and on the bank. There are also a small number of other birds and fowls, such as gray ducks that live on fish in the lake. When spring comes and warm air from the Bay of Bengal blows into the Ngari Plateau, groups of birds that have migrated from the cold plateau to the warm Southern Asian Continent the previous winter fly back to the islet. The months of May through September are the best season for observing birds. Herdsmen living on the lakefront often tell the story of dragons and monsters in the lake, which adds to the mysterious color of the lake.

And the most interesting thing about Panggong-tso is that water in the Chinese part is fresh, teeming with fish; however, in the Kashmir part, water becomes salty.