Dunagiri is a peak in the Kumaon region of Uttaranchal. The altitude of this peak is 7,066 m. It provides the longest view of the Himalayas in this region of Kumaon & Garhwal.  The other names with which this place is referred are Dunagiri, Doonagiri, or Drongiri. This place is majorly known for the Shakti temples that are famous in the region of Kumaon. This temple is also referred to as Dunagiri Devi temple.

As per the belief of the people belonging to this region, the place has been visited by many savants who later built their respective ashrams at this place. A few of these sages can be named as Garg Muni, Sukhdev Muni, etc. It is after the name of Garg Muni that river Gagas was given while a place named Sukh Devi also belonged to this region where the ashram of Sukhdev Muni was located. When Lakshman was bowed down by an arrow shot by Indrajit during the period of Ramayana, Hanuman Ji brought the Sanjivani herb from Dronagiri or DronagiriMountainto to save Lakshman’s life. Pandavas also stayed at this place for some time during their unspecified travel movement. Guru Dronacharya one of the gurus of Pandava also devoted his time to practice his tapasya at this place.

During the medieval times in 9th century CE Adi Shankaracharya moved to this place to begin monastic orders.

Dunagiri is mentioned in Manas khand of Skanda Purana. Dunagiri Devi is described as Mahamaya Harpriya (Manaskhand, 36.17-18). Manaskhand of Skandpuran bestows Dunagiri with the title of Brahm-parvat (Divine Mountain). Among all the Shakti temples of Kumaon, Dunagiri is counted amid the most ancient ‘Sidhh Shaktipeeth’, as a primary ‘ugra’ (intense) ‘peeths’ – called ‘Ugra Peeth’. This Shaktipeeth in its essence has been influenced over time by Shaiva, Vaishnav, and Shakt practices.

Source:

http://www.indiamapped.com/mountain-peaks-in-india/dunagiri/

http://www.summitpost.org/mt-dunagiri/330396