[2][3][4] The mountain range is made up of uplifted and folded sedimentary rocks consisting of weathered soft sandstones and shales.

[8] On the eastern side of the mountain range lies the Tambunan Valley at 800 metres (2,625 ft) which is mainly terraced paddy fields, and groves of bamboo border the north-eastern part of the protected park.

[10] Through the Bornean Biodiversity and Ecosystems Conservation Programme (BBEC), a technical co-operation existed between the government of Sabah and the Japan International Cooperation Agency (JICA) to innovate the Community Use Zone (CUZ) concept as a management option to address the issues concerning indigenous communities living and utilising resources within the protected areas.

In 2014, the range was recognised as a UNESCO Biosphere Reserve, becoming the second Malaysian site to be so designated, after Chini Lake in the state of Pahang on the peninsular side.

[12][13][14] The Crocker Mountains Forest Reserve area has a wide range of floral and faunal diversity and has the highest diversity of nocturnal insects in all the 20 forest reserves surveyed within the Heart of Borneo area in Sabah; it has recorded a number of endemic species.