The original inhabitants of Sikkim are said to be Lepchas. They existed much before the Bhutias and Nepalese migrated to the state. Before adopting Buddhism or Christianity as their religion, the earliest Lepcha settlers were believers in the bone faith or mune faith. This faith was basically based on spirits, good and bad. They worshipped spirits of mountains, rivers and forests which was but natural for a tribe that co-existed so harmoniously with the rich natural surroundings. The Lepcha (Zongu) folklore is rich with stories. The Lepcha population is concentrated in the central part of the Sikkim.

Nepalese appeared on the Sikkim scene much after the Lepchas & Bhutias. They migrated in large numbers and soon became the dominant community. The Nepalese now constitute more than 80 % of the total population. The Nepali settlers introduced the terraced system of cultivation. Cardamom was an important cash crop introduced by the Nepalese.

They are the people of Tibetan origin. They migrated to Sikkim perhaps somewhere after the fifteenth century through the state of Sikkim. In Northern Sikkim, where they are the major inhabitants, they are known as the Lachenpas and Lachungpas. The language spoken by the bhutias is Sikkimese. Bhutia villages are as large as those compared to those of Lepchas.