The biggest lake in the eastern region of Mongolia is Buir Lake. The lake is located 311 km distant from the east of Choibalsan city and is the fresh water lake where the most water birds gather in Mongolia." In 2004, the Buir Lake was included in the Ramsar List of Wetlands of International Importance according to the Ramsar Convention." The convention is the one of the biggest documents for conservation and sustainable utilization of wetlands, especially the place where water birds settle down most. There is 3-5 meter long sand embankment which was created from waves in the south of the lake. The average depth of the Buir Lake is seven meters. The Khalkh Gol River flows in the Buir Lake while Orshuun River flows out of it. There are 34 species of six clans of fish, 49 species of floating water weed, 5 species of floating animals and 4 species of pearl oysters in the lake. The Buir Lake is the lake with the most fish and most types of animals and birds in Mongolia. In addition, the longest water border of Mongolia continues in the lake. If you decide to travel to the richest lake in Mongolia, it is located 942 km distant from Ulaanbaatar.