Uureg lake is located in Sagil sum, Uvs province. Large and beautiful Uiireg Nuur (1425m above sea level) is surrounded by stunning 3000m- plus peaks, including Tsagaan Shuvuut Uul (3496m), part of the Uvs Nuur Strictly Protected Area. The freshwater lake has some unidentified minerals and is designated as 'saltwater' on some maps, so it's best to boil or purify all water from the lake.
The lake is great for swimming (albeit a little chilh) and locals say there are plenty of fish. The surrounding mountains are just begging to be explored.