Mahendragiri, also known as Mahendra Mountain, is one of the seven kulaparvatas (a family of mountains) in Hinduism. Reference to these mountains are found in almost all the Puranas - Vishnu Purana II.3.3; Bhagavata Purana V.19.16; VII.14.32; Brahmanda Purana II.16.18; Matsya Purana 114.17.18; Vayu Purana 45.89.
The relevant verse in Vishnu Purana (II.3.3) runs as follows
Mahendro malayah sahyah suktiman rikshaparvatah
Vindhyascha pariyatrascha saptatite kulaparvatah.
Mahendragiri stretches on the eastern ghats near the Ganjam District in Odisha. Its southern tips are still known as Mahendramalai.
The rivers which have their origin in Mahindra hill are Langalini, Vamsadhara and Mahendra (Vayu Purana 45.106).
The last one is also known as Mahendratanaya and still flows by Parlakimedi (Brahmanda Purana III 44.36) (46.29).
Bhagavata (X 79.12) state that sage Parasurama did penance on this hill for twelve years each on two different occasions.
According to the Mahabharata (Adi Parva, Chap 129), after exterminating the kshatriyas, Parasurama made this hill his abode. Vayu Purana (77.17-18) and Matsya Purana (22.44) specify a particular banyan tree on Mahendragiri under which funerary sacrifices are especially recommended.
Brahma is said to have performed a yajna on this mountain. Hanuman, the son of wind God, visited the mountain when he was on his mission to find Sita (Rama’s consort). The presiding deity of this mountain sits in the court of Kubera (Mahabharata Sabha Prava Chapter 10).
The Mahendra mountain and its king are mentioned by Kalidasa in his Raghuvamsa (VI.54) as the southeastern limit of Raghu’s digvijaya (conquests of all directions). In the later epigraphical records it is referred to as the southeastern limit of the wide conquests of cakravartin (emperor), e.g. Yasodharman of the Mandasor inscription.