Dedicated to Lord Shiva, Vadakkunnathan Temple is located in the beautiful town of Thrissur. The temple is also known as Thenkailasam and Vrishabhachalam and is one of the largest and ancient Shiva temples in the state. Located behind the Shiva's shrine is the shrine of goddess Parvati. The temple complex houses two more shrines dedicated to Rama and Sankaranarayana respectively. The idols of these heavenly deities were consecrated in the temple by Parasurama (the sixth avatar of lord Vishnu).

Covering an area of around 9 acres, the temple is surrounded by a massive wall. There are four towered entrances to the temple. Reflecting a wonderful example of the Kerala style of architecture, Vadakkunnathan Temple is decorated with arresting murals depicting various scenes from the great Hindu epic Mahabharata. The wood carvings are also notable. Lord Vadakkunnathar(Shiva) is worshiped in the temple in the form of a mound of ghee (clarified butter). Shivalingam is enclosed within the ever growing mound of ghee. And the interesting thing is that the ghee mound remains solid despite the presence of numerous lamps inside the sanctum sanctorum.

The festival of Shivratri is celebrated with great enthusiasm in the Vadakkunnathan Temple. Devotees from far and wide come to participate in the festival.