The boundary description as per the notification is as follows:
North:- Starting from Ottakombumala (hill point 2164) on the south western corner of Tirthalar proposed reserve forests, thence along the southern boundary of the said reserve till it reaches the northeastern corner of Mannavan shola reserve thence along the northeastern boundary of the said reserve up to Madavarimala, thence northeast along the southern boundary of Idivara Shola reserve passing along hill points 2153,2104, 2199, 2132, 2127 (Velligirimala)
East:- Starting from hill point at 2127 (Velligirimala) runs along the eastern boundary of Idivara Shola Reserved Forests and Pullaradi Shola Reserved Forest till it reaches the south eastern corner of Pullaradi Shola Reserved Forests adjoining the boundary of Kannan Devan Hills village concession lands.
South:- Starting from the south eastern corner of Pullaradi Shola reserved Forests runs more or less south along the southern boundary of Pullaradi Shola Reserved forests, Idivara Shola Reserved Forest and Mannavan Shola reserved Forests adjoining to the Northern Boundary of Kannan Devan Hills Village Concession lands till it reaches Tirthamala.
West:- Starting from Tirthamala runs along eastern boundary of Mannavan Shola Reserved Forests till it reaches hill point 2164, Ottakombumala.
The legal boundaries of ASNP is already been surveyed up to 75% and marketed with permanent cairns and the remaining area needs to be demarcated with cairns.
The Park has an area of 32.85 km2 (as per the GIS cell at Forest Headquarters) where as the notified extent is only 7.50 km2. Some discrepancies have been noticed with regard to the area of the three Reserve Forests. For instance, there is a vast difference in the area of the Shola Reserves as notified in 1901 under section 18 of regulation II of 1068 and the areas indicated on the map. This has been specially noted in the Working Plan for the Moovattupuzha part of Malayattur Division for the period from 1951-52 to 1966-67 by Sri. T.P. Viswanathan. According to the Working Plan, the area of three Shola Reserves (Mannavan, Pullaradi and Idivara Sholas) is 9100 acres (36.82 km2) where as the notified area is only 7.50 km2.
As per the GPS survey conducted by KFRI, the extent of the Park is 43.35 km2. Park authority has also carried out GPS survey along the forest boundary presently maintained by them which indicates an extent of 39.02 km2.
On the northern side, the Park is bordered by the forests of Marayoor Sandal Division and a part of Chinnar Wildlife Sanctuary. The eastern side is bordered partly by the Kurinjimala Sanctuary. On the southern and western side are the forests of Kannan Devan Hills and the tea estates. The Park provides ecological connectivity between the Anamalai Tiger Reserve, proposed Palni Hills National Park and the forests of Kannan Devan Hills.
The shola forests adjoining the western boundary of Idivara Shola Reserve Forest of the Park though falling in the jurisdiction of Marayur Division have not yet been declared as RF and are are categorized as revenue lands. The lower portion of this land has recently been identified and surveyed for distribution. Similiarly, the forests of KDH adjoining the southern and western flanks of the Park, though proposed for notification as RF still remain as revenue lands.
The plantations are not clearly demarcated on the map. The rights of the Muduvan tribes have also not been settled yet. At present, the area is managed as a single unit.