The Blog,
http://shanthiraju.wordpress.com/temples-within-chennai/
contains a page 'Temples within Chennai' - a comprehensive list of
ancient temples within Chennai city, more than 200 temples have been
listed. It also has a page 'Temples around Chennai', a comprehensive
list of ancient temples around Chennai.
Around 300 temples have been marked out geographically in
http://www.platial.com/raju0704/map/85205#Temples_of_Tamilnadu

Temples in North Chennai

Till a few months back I was thinking of North Chennai (Ponneri/
Gummidipoondi region) only as a polluted and under-developed area
(compared to South Chennai) but now I realize that this is true only
to about 15 kms from Parrys. Beyond that, it is the most beautiful
region of the Chennai surroundings with plenty of greeneries, lakes
and 'not-so-crowded ancient and sacred temples'. Initially I knew only
the Kalahasthi temple in this region and on hearing about Thirukkallil
and Siruvarpuri, first I visited them along with Periyapalayam. Then
on coming to know about Devadanam, I visited Devadanam and
Andarkuppam. Then I made my 3rd visit to Suruttapalli and Pancheshti.
Now I just made a trip for the 4th time to Ariyathurai, Pancheshti
(again), Chinnakavanam and Perumpedu. Even now, I understand this is
only the tip of the iceberg. This is the region of focus for Agasthiar
- he had installed a whopping 108 temples just between the
Kuchasthalai and Brahma Aranya rivers (but only a few exist now); this
is the area of Lava-Kucha, twin sons of Lord Rama, where they had been
trained at Valmiki Ashram here. Villivakkam, Vadamadhurai,
Siruvarpuri, Pancheshti, Puduvaayal, Thirukkallil and Chinna kavanam
are some of the Agasthiar's temples that exist today. Chinna kavanam
Nootretteswar is the 108th temple in this series. In most temples, the
main deity will be called Agastheeswarar and the Goddess will be
called Anandhavalli. Since this region is a very sacred and blessed
one, there are many lakes around and the water resource is aplenty and
is supplying to the entire Chennai.

Nootretteswarar Temple at Chinna Kavanam

The temple at a place called Chinna Kavanam 3 kms from Ponneri has a
2500 years old rare tree called Eru Azhinjil (or ankola) which has an
unique importance. Its fruit ripens, falls on the ground and after the
essense is eaten by ants and other insects, the seeds get attracted to
the parent tree like a magnet, signifying that the final destination
of the human beings being the lotus feet of the lord.
When Agasthiar worshipped Lord Shiva with a hand made Shivalingam from
the river sand with a lingam per day for 108 days, on the final day,
all the 108 lingams got merged into a Vinayagar and is present under
the Ankola tree as a Swayambu Vinayahar.
More details in 'Raju's Temple Visits' travelogue:
http://shanthiraju.wordpress.com/

Sri Ananthavalli sametha Sri Varamoortheeswarar temple at
Ariyathurai (Kavarapettai)

This 6000 years old temple is present in the Kolkatta highways at
around 35 kms from Chennai near Kavarapettai at the banks of Araniyar.
Lord Krishna stood here as a Aswatha tree for 1000 years. Water,
believed to be from River Ganges, is flowing out perennially all
though the year, though in small quantity. Due to this, the place is
considered more sacred than Kasi
More details in 'Raju's Temple Visits' travelogue.
http://shanthiraju.wordpress.com/

Pancheshti

Here Agasthiar stayed for many years and conducted five yagnas (Pancha
- five, Ishti - Yagna and that's why Pancheshti). There are many
beautiful sculptures in the outer and inner walls of the Rajagopuram.
This is a parihara sthalam and there is an 'Agasthia Theertham' temple
tank which was created by Agasthiar by spitting a little water after
drinking the complete sea.
More details in 'Raju's Temple Visits' travelogue:
http://shanthiraju.wordpress.com/

Pancha Brahma Sthalams:

The Brahma Aranya river, considered to be created by Lord Brahma
flows, in North Chennai (Ponneri side) and merges with sea at
Pazhaverkadu. Many sages have meditated at the banks of this river and
created many temples. Out of these, in five places they have contained
all their meditative powers into the Shivalingams and built the
temples. They are called Pancha Brahma Sthalams, representing the five
faces of Lord Shiva and they are:

§      Ramagiri alias Thiru Arikarai in Andhra near Suruttapalli/
Nagalapuram represents Eesana face of Lord Shiva
§      Pallikondeswaram alias Suruttapalli represents Thath purusha face
§      Vamadhevapuram alias Arani near Periyapalayam (not North Arcot)
represents Vamadheva face.
§      Varamoorthy Kshethram alias Ariyathurai represents Sathyojatha
face.
§      South Gokaranam alias Chinthamaneeswaram - Kattur near Minjur the
place where Brahma Aranya river merges with sea represents Agora face
of Lord Shiva.

All these temples are many thousand years old and since they have been
created by Sages, the base of the lingam (avudayar) are in square
shape.

Regards,
Raju