Central Kalimantan is a huge province, covering 153,800 square kilometers of south-central Borneo from the Schwaner Mountains to the Java Sea, most of which is jungle. The northern area is mountainous and difficult to reach therefore the area is the least visited region on the island. The central area is dense tropical forest. The southern area is swampy and has many rivers. The climate is hot and humid.

The tree Dayak sub-tribes who inhabit this province are the Ngaju, Ot Danum, and Ma’anyan Ot Siang. The Nagju are nomadic, adhering to old Kaharingan religion, which is a form of ancestor worship mixed with elements of animism. With approximately 6,000 people, the Ot Danum is the largest among the tree subtribes. The Ot Danum live in longhouses which sometimes have as many as 50 rooms. The women are known for their skill in plaiting rattan, palm leaves, and bamboo. Like other Dayaks, the men are good hunters, using simple tools. The Dayak’s people of this region are perhaps Borneo’s most traditional and the Kaharingan religion, which is the traditional belief of the Dayaks in the hinterland of Central Kalimantan roots here. Building styles, statues and carvings have been influenced by the Hindus, Chinese, and Hindu-Javanese. Aside from their aesthetic properties, many objects are appreciated for their magic value.

Kalteng has 153,800 square kilometers of swamp, jungle and forest which are split by a series of roughly parallel rivers flowing from the Schwaner and Muller ranges in the north to the Java Sea in the south. The coastal extremities of the rivers are thinly populated because of swamp lands, choked with Nipa palms and Mangroves.