Hoh Xil contains over 100 lakes of various sizes, many of them unnamed, formed in depressions across the plateau by glacial melt and permafrost dynamics. The lakes range from small, shallow seasonal ponds to the considerable Hoh Xil Lake itself — a brackish body of several hundred square kilometres in the plateau's interior. The lake district is largely inaccessible to the public and requires special permits, but parts of the wetland system are visible from the highway and the reserve station area.
The wetlands support breeding populations of bar-headed geese, brown-headed gulls, and several species of sandpiper and plover. The bar-headed goose is the plateau's most famous avian resident — it crosses the Himalayas at altitudes exceeding 7,000 metres during its migration, breathing air that would incapacitate most vertebrates. Seeing a skein of these birds against the plateau sky in the late-afternoon light is one of those natural moments that stays with you.