Nunuk Ragang is a site traditionally considered as the location of the original home of the ancestors of the Kadazan-Dusun natives who inhabit most of northern Borneo. The site, nearby a village named Tampias, is located at the intersection of the left (Liwagu Kogibangan) and right (Liwagu Kowananan) branches of the Liwagu River to the east of Ranau and Tambunan in Sabah. The two river branches joined up to flow into the Labuk river and drain out into the Sulu Sea. At the site, and under a giant banyan tree, a settlement referred to as Nunuk Ragang was founded. The giant banyan tree was said to be able to give shade to a longhouse sheltering 10 families in it. The legend about Nunuk Ragang had been passed down via oral traditions to the younger generations. No archaeological dig has been carried out to establish the veracity of the legend.
In 2004, the quasi-government group Kadazan-Dusun Cultural Association (KDCA) set up a memorial near Tampias at the site of what they believed to be the original village. The word "tampias" means "sprinkled" or "dispersed". The memorial was built in the form of a huge fig tree. The association conducts annual pilgrimages to the site, timed to coincide with the inauguration of its paramount chief, the Huguon Siou.
The name Nunuk Ragang is derived from two Kadazan-Dusun words "nunuk" which refers to the "banyan" tree and "ragang" which is a shortened form of the word "aragang" which means "red colored". The two words together therefore refer to a red coloured banyan tree. Zoologically, there is no known banyan tree with red leaves or trunk. This fact has contributed to the mystery surrounding Nunuk Ragang but the most logical reason for naming the settlement as "red banyan" is that the settlers, in their attempt to attract attention to their presence, intentionally made the banyan tree to appear red. The Kadazan-Dusun has a fondness for riddling, giving names to places, things and actions in terms other than the actual.
At the Nunuk Ragang settlement began the belief system and culture of the Kadazan-Dusun. There was no word for "religion" among the ancient Kadazan-Dusun and to them it was just a sort of relationship between the seen and the unseen. Some people would equate this to Animism. This belief system centers largely on their livelihood and rituals so as to maintain the balance, order and harmony between themselves and between them and their environment, which consequently provide conditions for bountiful cultivation and harvests and continued existence of the race. At the settlement also began Momolianism, a philosophical system, which when coupled with the belief system, had guided the life of the Kadazan-Dusun people up to the present age. Surrounded by thick primary forest teeming in wildlife, nature and nurture became the foundation for the birth and growth of the belief system and cultural heritage of the Kadazan-Dusun.
The Dusunic-speaking peoples, descendants of the pioneers at Nunuk Ragang, are today agriculturalists and paddy planting is the common occupation among them. But according to oral traditions passed down from elders, the Nunuk Ragang people were practising vegeculture. Vegeculture is the cultivation and propagation of plant food by utilising the suckers of plants such as the yam, the sweet potato and cassava, eliminating the needs for seeds and permanent storage thus facilitating rapid migrations. Bamboo and Rattan were the primary materials used for all forms of activities connected to home construction and storage. To light a fire the settlers used dried cottony bark scraped from the Polod palm tree. Metal, used for making dangol (short machete) and pais (carving knives) was already available, most probably through barter trading with coastal peoples. The Nunuk Ragang settlers also adapted to their environment by becoming hunter-gatherers and trappers. Salt, an important food enhancer and preservative was only intermittently available from the distant coastal region, prompting the Nunuk Ragang settlers to search out for sosopon (natural salt lick) frequented by wild animals. This persistent shortage of salt also gave rise to two important techniques, "memangi" and "manalau", for the preservation of meat and fish. Memangi produces "pinongian" or "bosou" (meat or fish preserved using the fleshy kernels from seeds of the Pangium Edule tree), and manalau, a smoked meat called "sinalau".
The possibility of further pinpointing the exact origin of the Kadazan-Dusun from before the Nunuk Ragang settlement was further enlightened during the official visit of Taiwan's minister of Council of indigenous People's, Icayang Parod in early June 2017. Masidi Manjun, Sabah minister of Tourism, Culture and Environment, referred to the numerous similarities particularly in ethnic languages between the indigenous peoples of Taiwan and the Kadazan-Dusun.