Location: Thang Hen Lake  is located Quoc Toan Commune, Tra Linh district, Cao Bang province . Features: This is a beautiful lake located in the 36 lakes in the mountains of our country, height above sea level thousands of meters.
Thang Hen Lake  in the middle of the mountains and the blue of her reach crops on the cliff reflecting in the water down, the lap winding bumpy cornering the underground quarry.Although it is not large compared with Ba Be Lake,  but also no less beautiful than Ba Be Lake 
Thang Hen Lake  diamond width is approximately 100m, 500m length, between forest white fillings, inlays black knob rugged rocks. The watershed is a large cave, cave water from flowing around the clock. Especially Thang Hen lake has two daily round of “tide” up and down. In flood water while the other lakes scarlet Thang Hen lake, the water is always blue. Season shallow water about 10m deep.
Thang Hen lake  also watch Thang Luong, between a mountain lake knob spectacular scenery.