The park is one of the most biologically diverse places in Madagascar, with many endemic species. The eastern flank of the massif is covered with humid forest, and humid grassland and scrub in the higher areas. On the western flank there is relatively dry forest. There are over one thousand species of plants, one hundred species of birds, and fifty-five species of frogs are known to inhabit the park.

The reserve covers 31,160 hectares (77,000 acres) covering much of the granite massif of the Andringitra mountains which rise above plains. The altitude of the reserve varies from 700 metres (2,300 ft) to the peak of the second highest mountain in the country, Imarivolanitra (formerly Pic Boby) at 2,658 metres (8,720 ft). The mean annual rainfall is 1,500–2,500 millimetres (59–98 in) and snowfall occurs in some years. Madagascar's lowest temperature, −8 °C (18 °F) has been recorded here. The Ampanasana, Iantara, Menarahaka and Zomandao rivers run through the reserve.

When someday comes you'll need to get in.

When someday comes you'll need to be able to get around.