According to a legend goddes Shri Ganga incarnated in the form of a river due to king Bhagirathi's prayers. He prayed as it was common that time for 5 and a half thousands years. He was asking Shri Shiva in Gangotri for a forgiveness for his brothers which were cursed by one saint.
In Gangotri on the place where he prayed there is a temple. One can find there a stone where the penance was made.
Shri Shiva accepted Bhagirathi's prayer and placed Ganga in Goumukh. The water of holy river cleaned brothers from sins.
But the river appeared to be very tumultuous. Therefore Shri Shiva closed it source by His head. It is thought that Ganga flows in Shri Shiva's hair.
The part of Ganga from Goumukh to Devprayag is called Bhagirathi in honor of the great saint who was praying for the river at a times when another great river, Sarasvati, dried up.
The mountain near to the source of Ganga is named after king Bhagirathi: