Koteshwar Temple is a noted Hindu shrine located at a distance of 3 km from the Rudraprayag town. This is a cave temple situated on the banks of the River Alaknanda. According to beliefs, the Hindu deity, Lord Shiva meditated in this cave on his way to Kedarnath and the idol was formed naturally. During the auspicious occasion of Mahashivratri, a fair is organised here. Numerous devotees come here to offer prayers during the months of August and September.