The Rai, also known as the Khambu, are one of Nepal’s most ancient indigenous ethnolinguistic groups. The Rai belong to the Kiranti group or Kirat confederation that includes the Limbu and Sunuwar ethnic groups. The traditional homeland of the Rai extends across Solukhumbu, Okhaldhunga, Khotang, Bhojpur and Udayapur Districts in the northeastern mountains of Nepal, west of the Arun River, in the Sun Kosi River watershed.

According to Nepal’s 2001 census, there are 636,151 ethnic Rai in Nepal, representing 2.79% of the total population. The Rai are divided into many different clan groups, including the Bantawa, Chamling, Dumi, Jerung, Kulung, Khaling, Lohorung, Mewahang, Thulung, Tilung, Wambule, Yakkha, and Yamphu. Some clans number only a few hundred members. The languages and traditional religion of the Rai are known as Kiranti.

More than 30 different Kiranti languages and dialects are recognized within the Tibeto-Burman branch of the Sino-Tibetan language family. The oral language is rich and ancient, as is Kiranti history, but there is no distinct written script.

The traditional Kiranti religion, apparently predating Hinduism and Buddhism, is based on ancestor-worship and the placation of ancestor spirits through elaborate rituals governed by rules called Mundum. Sumnima and Parohang are worshipped as primordial parents. Sikatakhu Budo, Walmo Budi, and Jalpa Devi, among others, serve as Kiranti deities. Most Rai practice a form of syncretic Mundum that combines elements of Hinduism and Lamaism with both Hindu and Buddhist practices and major festivals. A major Rai holiday is the harvest festival, Nwogi, when fresh harvested foods are shared by all. The pujhari or priest plays an important role in Rai communities.

Because of the fiercely independent nature of the Rai community and its location at the eastern end of the consolidating Nepali nation-state, the Rai were given exceptional rights of kipat autonomy and land ownership in their homeland of Majh (middle) Kirant.

Subsistence agriculture of rice, millet, wheat, corn and even cotton is the main occupation of the Rai although many Rai have been recruited into military service with the Nepali army and police, and the Indian and British Gurkha regiments.

Rai women decorate themselves lavishly with silver and gold coin jewelry. Marriage unions are usually monogamous and arranged by parents, although bride capture and elopement are alternative methods. Music (traditional drums and string instruments; yele, dhol and jhyamta), dance (sakela - chandi dance) and distilled spirits (arakha), are central to Rai culture.