Agasthyarkoodam is a -tall peak of the Pothigai mountain range of Tamil Nadu in the Western Ghats of South India. The peak lies on the border of Tamilnadu and Kerala. This peak is a part of the Agasthyamala Biosphere Reserve which lies on the border between the Indian states of Kerala (in Pathanamthitta, Kollam and Thiruvananthapuram districts) and Tamil Nadu (in Kanyakumari district, Tirunelveli district). The perennial Thamirabarani River originates from the eastern side of the range and flows into the Tirunelveli district of Tamil Nadu.