Mengda Heavenly Lake is located in the Dangrui-Wutai Mountain area, a branch of the Xiqing Mountains under the Bayan Har Range, in the eastern part of Xunhua Salar Autonomous County. It sits over 110 kilometers southeast of Xining.

The reserve spans 9,544 hectares, with an average altitude above 2,500 meters and a main peak rising to 4,178 meters. Located in the transition zone from the Loess Plateau to the Qinghai-Tibet Plateau, it belongs to the Aqinkajin-Dangrui Wutai Uplift Belt in terms of geological structure. The landform consists of fragmented loess hills with numerous steep slopes, precipitous cliffs and narrow V-shaped valleys.

Surrounded by towering peaks, the area is shielded from dry and cold air while exposed to warm southeast currents, bringing mild weather and abundant rainfall. The annual average temperature is 5.4°C. The large relative elevation difference creates varied climatic zones including warm temperate, temperate and cold temperate regions. The annual precipitation reaches 622.7 millimeters, 89% of which falls between May and September. Five gullies run south to north across the area and empty into the Yellow River.

Nestled in the middle of Muchang Gully is Mengda Heavenly Lake, a natural alpine lake covering nearly 20 hectares. It has an average depth of 10 meters and a water storage capacity of 2 to 3 million cubic meters. To the east of the lake stands a natural dike stretching over 200 meters from north to south, rising 50 to 70 meters above the water surface. Formed by retreating glaciers, it is a terminal moraine dam. In the southeastern part of the lake lies a fan-shaped waterfall, over 10 meters high and 7 to 8 meters wide. It surges vigorously in summer and turns into an ice waterfall in winter.

Though much smaller than Changbai Mountain Heavenly Lake and Tianshan Heavenly Lake, Mengda Heavenly Lake boasts unique charms. The peaks around Changbai Mountain Heavenly Lake are nearly barren; dense spruce forests grow far away from Tianshan Heavenly Lake. By contrast, Mengda Heavenly Lake is entirely encircled by thick forests that cover the land from the lakeshore all the way to the mountain tops. Its water also has a distinct hue: Changbai Mountain’s lake features varied shades of blue shifting with floating clouds; Tianshan’s lake presents a single tone of blue; while Mengda Heavenly Lake is emerald green, blending harmoniously with the surrounding woods.