Alagar Temple or Azhagar Koyil is dedicated to Lord Vishnu and has a long history. The history of the temple speaks about the Mandooga munivar who got redemption from his frog status by the Lord Kallazhagar. During the regime of Thirumalai Nayak in 1653, the ritual of relieving Mandooga Maharishi was shifted to Vandiyur village.

Millions of people gather at this place to see the Kallazhar River crossing function. This is usually held in the month of June. The temple has large gopurams and pillared mandapams. The main tower entrance is called Mukya Gopuram and the shrine of Karupana Swami is located here. The temple is covered by the tropical forests and there is a herbal garden here irrigated by the natural spring known as Devi Theertham or Noobura Gangai. Good number of Indian bison is seen in the forest and so the area is called Bison Valley.