The Tharu constitute the largest ethnic group of the Terai. They are spread across the length of Nepal's plains and also extend westward into the Kumaon foothills. The Tharu are probably the oldest and original inhabitants of the Terai. While they generally have Mongoloid features with dark-brown complexion, the Rana-Tharu of the western Terai claim Rajput ancestry.
Tharu language has been greatly influ¬enced by various Indo-Aryan languages such as Maithili in the eastern, Bhojpuri in the central, and Awadhi in western Terai. Tharu marriages are patrilocal within the tribe. A common feature of the Tharu commu¬nity is the joint family system of living in long houses.
Traditional Tharu religion consists of the worship of spirits, particularly of the forest. The family deity is located in the eastern corner of the house, where also sleeps the senior most family member. Tharus also revere two categories of ancestral deity: Goraiya is offered pig and Mainya is offered goat as sacrifice. The village shrine, called bhuinhar, is marked by several carved wooden boards erected on the ground where chicken, pigs and goats are sacrificed. The tribal priest is known as Guruwa, whose tradition still holds strong in inner Terai and western Terai villages. Tharus in these areas bury their dead in a common burial ground, while crema¬tion is common elsewhere.
Tharu huts have wattle walls and the thatch roof is usually covered with gourd creepers. The utensils include containers of gourd, earthen pots and mats woven from paddy straw. The houses are kept clean and the walls decorated with floral and animal motifs. The women adorn themselves with intricate ornaments that include bangles and necklaces of beads and coins.
Tharus live in compact villages, usually in the middle of a forest clearing. They are very familiar with jungle life and also fish in the streams. In agriculture, Tharus have developed elaborate irrigation techniques for agriculture. While some are rich landlords, the great majority of the Tharu population is made up of tenant farmers. Tharu is believed to be the largest Nepali tribal group after Magars.