The erstwhile Chinnar Reserve was notified as a Sanctuary in 1984. The original notification of the Chinnar Reserved Forest dates back to 1942 and the boundaries follow a jumble of cairn numbers and survey numbers. At present the boundaries are fully demarcated but in certain areas like Njavala-Ollavayal, the status is vague and may not correspond to the situation on the field.
The boundary description as per the notification is as follows:
North:- Starting from cairn No.1 at the trijunction of the boundaries of Coimbatore District, Marayoor Pakuthy and Kannan Devan Hills at the North West corner of the Reserve, the line goes in a nearly north easterly direction for about 5643/4 chains along the Chinnar River to cairn No.2 at a State Boundary Survey Stone on the bank of the Chinnar River, thence more or less east- south east for about 2141/4 chains along the above said river to cairn No.3 at the State Boundary Survey Stone on the bank of the river side of that Survey No. for about 11/4 chains to cairn No.4 at its south west corner. (This is also the Western most point of S.No.251/1/1). Thence nearly east along the south side of the S.No. 257/1/1 for about 333/4 chains passing cairns No. 5 to 15 to cairn No.16 at its south east corner. Thence nearly south for about 63/4 chains to cairn 17 thence nearly south for about 63/4 chains passing cairn No.18 and crossing the approach road to the P.W.D. camp shed to cairn No.19 at the right bank of the thodu flowing to Chinnar River – then nearly north along that thodu for about 103/4 chains to cairn No.20 at its junction with the Chinnar River (from cairn numbers 16 to 20 the boundary follows the Western, Southern and Eastern Boundaries of the area allowed for the P.W.D. excluding the same from the reserve.) thence nearly east along the Chinnar River for about 71/2 chains to cairn No.21, on its bank; thence nearly south east for about 43/4 chains passing 9 cairn number No.22, 23 to cairn No.24 on the West side of the approach road to the P.W.D. camp shed; thence east by slightly south for about 3/4 chains crossing the above road to cairn No.24A; thence nearly east- south east for 1 chain to cairn No.24B; thence nearly north-north east for 31/2 chains to cairn No.24C, thence east for 3/4 chains to cairn No.24D, thence north for 11/2 chains to cairn No.24E, thence west for 3/4 chains to cairn No.25; thence nearly north west for about 11/4 chains crossing the northern outlet road to cairn No.26 on the right bank of the Chinnar river situated 81 links north west of the State Boundary Survey Stone between distance 438 and 500, (from cairn 21 to 26 the boundary follows the Western, Southern and Eastern boundaries of the area allowed for the Excise Office Cart Stand and tollgate excluding the same from the reserve); thence nearly east along the same river for about 11 chains to cairn No.27 at the Revenue Stone at the North West Corner of Survey 261/1; thence nearly South West along its West side for about 11/4 chains to cairn No.28 at its South West Corner, thence along the West, South and East sides of Survey No. 259/1 for about 63/4 chains passing cairn Nos. 29 to 31 to cairn No.32 at its North East corner; thence nearly East along the Chinnar River for about 721/2 chains to cairn No.34; it is junction of Pambar River with Chinnar River.
East:- Thence nearly South- South West along the left bank of the Pambar River for about 43/4 chains to cairn No. 36 situated on the left bank of Athioda stream at its confluence with the Pambar thence nearly South South-East along the Athioda Stream (the boundary between Travancore and Coimbatore District) for about 4511/4 chains to cairn 37 where Athiodai cross the State Boundary for about 1263/4 chains to cairn No.38 at the top of Jambu malai peak at the trijunction of Coimbatore and Madurai Districts and Travancore State (This peak is locally known as ‘Chinna Chambu Malai’).
South and West:- Thence nearly south west along the state boundary for about 38 chains to cairn No. 39 at the boundary stone at the north-east corner of survey No. 72/1 of Kothukombu Pakuthy at the trijunction of Keelanthur and Kottakombu Pakuthies of Devikulam Taluk and Palani Taluk of Madurai District (This place is locally known as Vellimalai); thence in the same direction for about 631/2 chains along the boundary between Keelanthur and Kottakombu Pakuthies to cairn No. 40 at “Chenkannimala” thence nearly West South-West along the above Pakuthy boundary for about 531/4 chains passing Velliyangiri hills to cairn No. 41 at the Village 10Boundary Stone at the trijunction of Kilanthur, Kootakombu and Kanthaloor Pakuthies (this place is also known as Vattachola lower); thence nearly North West for about 231/2 chains to cairn No. 42 at a Village Boundary Stone between Kanthaloor and Kilanthur Pakuthies, (this place is also known as Vattachola Upper) thence in same direction but more to the West for 30 chains to cairn No. 43 on the right bank of the Vannanthorai Stream ; thence nearly West North West along the right bank of the above stream for about 1091/2 chains to cairn No. 44 (here the stream leaves the boundary)) thence nearly North for about 21/2 chains to cairn No. 45 it has theodolite stone at the South East Corner of Survey No. 300/1 of Kilanthur Pakuthies thence along the East side of the above survey Number for about 9 chains passing cairn No.s 46 and 47 to cairn No. 85 of Vannathorai Sandal Wood Reserve Block No. 11 at the theodolite stone at the North East Corner of Survey No. 300/1 thence along the Eastern, Northern and Western Boundaries of that reserve to its South West Corner at cairn No. 104 at a theodolite station on the right bank of the Kalikilavan Odai, thence nearly South West along the same bank of the said Oda for about 8 chains to its junction with the Vannanthorai River, thence along the right bank of the Vannanthorai River first nearly West North – West and then North-North West for about 1401/2 chains to cairn No. 48 at its junction with the Pambar River thence nearly North along the right bank of Pambar River for about 1071/2 chains to cairn No. 49 thence nearly North West for 21/2 chains crossing the Pambar River to cairn No. 50 on the left bank of Natchimuthu Odai at its confluence with the Pambar River: thence nearly South West along the left bank of the Natchimuthu Odai for about 831/4 chains to cairn No. 51 about 3/4 chains South of the theodolite stone at the South East Corner of Survey No. 256/1; thence nearly North West along the East side of the above Survey Number for 3 chains to cairn No. 52 at theodolite stone at its North East Corner; thence more or less West for its Eastern edge; thence more or less West for about about 7 chains to cairn No. 53 at the first quarter of the 29th mile of the near road on its Eastern edge; thence crossing the road for 1 chain to cairn No. 54 on its Western edge; thence along the same edge of the road first nearly West South West and then nearly North West for about 392 chains to cairn No. 65 where the Natchimuthu Odai crosses the above road; thence along the left bank of the same Odai for about 61/2 chains to cairn No. 56 on the Southern side of Survey No. 227/2; thence along and Southern side of Survey No. 11227/2 and Southern, Eastern and Northern sides of Survey No. 227/1 for about 181/4 chains passing cairn No. 57 to 64 to cairn No. 65 at the North West Corner of Survey No. 227/1 on the left bank of the Natchimuthu Odai for about 483/4 chains to cairn No. 66 at the theodolite stone at the South West Corner of Survey No. 2881/2; thence skirting the Southern Eastern and Northern sides of the above Survey No. for about 261/4 chains passing cairn No. 67 to 75 to cairn No. 76 at the theodolite stone at the North West Corner of the Survey Number on the left bank of the Natchimuthu Odai; thence first nearly North West and then West North -West along the same bank of the above Odai for about 156 chains to cairn No. 77 on the same bank Nandulamalai thence nearly South West for about 160 chains through Sy. No. 286/1/1 of Marayoor Pakuthy passing cairn Nos. 78 to 80 to cairn No. 81 at a boundary stone on the boundary between the Kannan Devan Hills and Marayoor Pakuthies to the North of Kumarikal malai and to the East of Poovar thadam thence nearly North West along the above boundary for about 146 chains passing cairns 82 to 91 (this line crosses the Poovar between cairn Nos. 85 and 86) to cairn No. 1 at the starting point on the Northern Boundary.
On the North and East, it shares a 30 km common boundary with the Anamalai Tiger Reserve of Tamil Nadu. On the West, it is bordered by the Eravikulam National Park. On the southern side, it is bordered by the Reserve Forests of Marayoor Sandal Division, part of Kurinjimala Sanctuary, and also by Revenue Lands. The Park provides ecological connectivity between the Anamalai Tiger Reserve and Eravikulam National Park.
The description of internal boundaries demarcating the private rights admitted within the reserve is specified in the reserve notification of 1942. The boundaries of the rights admitted for the PWD quarters at Chinnar and the enclosure at Ollavayal is vague and needs to be verified on field.
Earlier the Sanctuary area was divided into two Sections namely Chinnar and Karimutty and internal boundary for the sections were specified. Forest Station system was introduced in 12August 2005 and the entire sanctuary was brought under one forest station Karimutty. Hence these section boundaries became irrelevant.