Thirupachur (Thirupasur), a village near Thiruvallur, is home to the Vachishwarar temple, one of the Padal Petra Sthalams or temples wherein the deities have been praised in the Tamil verses of the Nayanmars or sixty-three important Saivite devotees. The presiding deity of this temple is Vachishwarar, a Siva Linga worshipped by the famous Nayanmars Thirunavukkarasar (Appar) and Thirugnanasambandar in the 7th century AD. While Thirugnanasambandar calls this deity Pasurnathar, inscriptions mention the name as Thirupasur Udaiyar.
This temple’s Sthala Puranam or traditional story states that this Siva Linga was buried in a bamboo forest here. A cowherd saw one of his cows regularly pouring milk at a particular place in this forest and informed the king. When they dug the ground, the Linga was discovered and consecrated here. There is a bamboo tree inside this temple as it is the Sthala Vriksham (sacred tree). The Siva Linga is therefore worshipped as a Swayambhu (self-manifested).
This large temple faces east, but the main entrance, with a tall gopuram, is on the south. Ahead is the entrance which has a long corridor with numerous Chola era pillars and multiple shrines including the east-facing sanctum for Goddess Thangathali Amman (Parvati). This is rare as Parvati shrines usually face south in the Siva temples of Tamil Nadu. A prakaram (circumambulatory passage) runs around this shrine. An interesting feature of this temple is a cluster of eleven stone Vinayakas in a group on one side of the corridor, which is called ‘Vinayaka Sabhai’. Sanctums for Subramanya with consorts and Navagrahas are also seen in this corridor, at the end of which is the principal shrine for God Vacheeshwarar, facing east, close to which is a utsava-murti (processional image) of Nataraja and Sivakami with devotee, Manikkavachakar. The main sanctum, square in shape but with a gajaprishta (apsidal) shikhara, has an inner prakaram, with Virabhadra Svami, Svarna Bhairavar and other images. The devakoshtas (niches) on the outer walls of this shine have Ganesha, Dakshinamurthi, Lingodhbhavamurti, Brahma, and Durga. The image of Durga is unique as the head of Mahishasura is not under Her feet.
A Sri Chakra, consecrated by Adi Sankaracharya, is in the ardha-mandapa in front of the central shrine. It is interesting to note that the sanctums for Vacheeshwarar, Thangathali Amman, Vinayaka Sabhai and Subramanya all face east, and that the Vinayakas and Subramanya are inbetween the shrines of Siva and Parvati. The bali-pitham, dvaja-stambham (flag-post) and Nandi are on the east side, directly facing Vacheeshwarar. The entrance on the east is a doorway, sans gopuram. A few Chola inscriptions have been discovered here, belonging to the reigns of Rajaraja Chola I, Kulottunga Chola I, Rajaraja II and Kulottunga Chola III. Among the many festivals celebrated is the annual Brahmotsavam which is for fifteen days.
Thirupachur is situated on the Thiruvallur-Thiruttani road, close to Thiruvallur.