Lake Balinsasayao has a surface area of 76 hectares (190 acres) and maximum depth of around 90 metres (300 ft).

The smaller Lake Danao, on the other hand, has a surface area of 30 hectares (74 acres) and maximum depth of around 58 metres (190 ft).

[6] The twin lakes and their surrounding primary and secondary dipterocarp forests serve as the watershed for southern Negros Oriental.

[5] The Balinsasayao natural park is an important bird area which supports at least 114 avifauna species including the critically endangered Negros bleeding-heart and Visayan wrinkled hornbill, and other endangered birds such as the Negros striped babbler, flame-templed babbler, Japanese night heron and white-throated jungle flycatcher.

[5] At least 27 mammalian species have also been documented in the area such as the endangered and endemic Philippine spotted deer, Visayan warty pig, Visayan leopard cat, Negros shrew and large fruit bats such as Philippine naked-backed fruit bat, Philippine tube-nosed fruit bat, giant golden-crowned flying fox and little golden-mantled flying fox.