The Jaunsari tribe has got the highest number of people in the state. Jaunsari tribe has got salient body features, resembling that of both the Mongoloid as well as Indo -Aryan groups who have settled in the Himalayan provinces. They claim themselves as the descendants of Pandavas of Mahabharata. They dwell in in Jaunsar in Dehradun, Jaunpur in Tehri Garhwal, Rawain in Uttarkashi and Purola region of Uttar Pradesh. They represent the three main classes, the Khasas as Rajput and Brahmins as high caste, the Luhar, Badai, Bajgi the artisan as the middle class and Harijan Dom, Koli, Kolta, Koi, Auj as the low caste. Khasa play the dominant and leading role in the social, economic and political life of all sections of polyandrous people. Among themselves they speak Jaunsari. Their common language of communication is Hindi.

To sustain their livelihood, majority of these Jaunsari tribal communities have taken up the profession of labourers who use to work diligently in the forest grounds or in farms of the rich people. Since these Jaunsari tribes posses small amount of land, they could not adapt to cultivation. They depend on agriculture and animal husbandry to eke out their living. The Khasas have been land holders and cultivators. The traditional craft is weaving.

The entire society of Jaunsari tribes is divided into several castes, namely Koltas and Khasas, each having their unique traits and ethnicity, which as a whole constitutes the culture of the Jaunsari tribal community. Marriage plays a vital role among the Jaunsari tribe. Amongst the Jaunsari tribes, the practice of polyandry is in vogue.

Festivals and fairs are an integral part of the people of Jaunsari tribal community. Bissu, a type of fair marking the harvesting, is quite a significant one. Song and dance is part and parcel of the life of these Jaunsari tribes. Both men and women dance with the rhythm of melodious songs and music especially at the time of festivals and various social functions and affairs.

Mahasu Devta is one of the principal deities whom each and every tribe of the Jaunsari community reveres. The devotees have brought out a procession every year in the month of August. Even a fair has been organized at that time.