Sasthamangalam Mahadeva temple is located on the Sasthamangalam – Peroorkada road in Thiruvananthapuram. The 10-day annual festival in Sasthamangalam Mahadeva temple is observed in Dhanu month and it ends on Thiruvathira with Arattu.
Shiva is worshipped in the form of a Shivling noted for its breadth. The sreekovil faces east.
Ganapathy, Murugan and Sastha are the Upa Devatas in the temple. Outside the temple complex on the banks Killi River there are separate areas of worship for Goddess Kali, Veerabhadran, Nagaraja and Nagayakshi.
Full pradakshinam is allowed at Sasthamangalam Mahadeva Temple. In most Shiva temples only 3/4th pradakshinam is allowed.
The temple is more than 800 years old. It is said that Travancore king used to visit three temples in the region in procession and Sasthamangalam Mahadeva temple was one among them.