Agastyaarkoodam is one of the peaks in the Western Ghats of Thiruvananthapuram District of Kerala and Tirunelveli District of Tamil Nadu, India.[1] This peak is a part of the Agasthyamala Biosphere Reserve which lies on the border between the Indian states of Tamil Nadu, Tirunelveli district and Kerala, Thiruvananthapuram district. The perennial Thamirabarani River originates from the eastern side of the range and flows into the Tirunelveli district of Tamil Nadu. It is 1,868-metres (6,129 ft) tall.

Agastyaarkoodam is a pilgrimage centre for devotees of the Hindu sage Agastya, who is considered to be one of the seven rishis (Saptarishi) of Hindu Puranas. In Tamil traditions, Agastya is considered as the father of the Tamil language and the compiler of the first Tamil grammar called Agattiyam or Akattiyam. There is a small stone statue of Agathiyar at the top of the peak and the devotees can offer pujas.

Agasthyamala Biosphere Reserve is among 20 new sites added by UNESCO to its World Network of Biosphere Reserves in March 2016. The International Co-ordinating Council added the new sites during a two-day meeting on 19 March 2016 in Lima, bringing the total number of biosphere reserves to 669 sites in 120 countries, including 16 transboundary sites. The biosphere reserve includes close to 300 rare bird species and more than 200 medicinal plants endemic to this region.