Overview
Yamunotri, also spelt Jamnotri, is the source of the Yamuna River and the seat of the Goddess Yamuna in Hinduism. It lies at an altitude of 3,293 metres (10,804 ft) in the Garhwal Himalayas, approximately 150 kilometres north of Uttarkashi, the headquarters of Uttarkashi district in the Garhwal Division of Uttarakhand, India.
The shrine is one of the four sites in India's Chota Char Dham pilgrimage circuit, and is the westernmost of the Garhwal Himalayan shrines. It is perched atop a flank of the Bandarpunch mountain. The chief attraction at Yamunotri is the temple dedicated to the Goddess Yamuna, along with holy thermal springs at Janki Chatti, situated about 7 km away.
The actual source of the Yamuna is a frozen lake of ice and the Champasar Glacier, located on the Kalind Mountain at a height of about 4,421 metres above sea level, around 1 km further up from the temple. As the source is not easily accessible, it is not generally frequented by pilgrims. The shrine has accordingly been located at the foot of the hill, where pilgrims offer puja at the temple itself.
References
Adapted from the English Wikipedia article on Yamunotri.