Omkareshwar temple is situated at the Narmada river in Ujjain, Madhya Pradesh.
It derives it name from “Om” as it is situated on the river island which is in the shape of Om.
Once sage Narada visited Vindhya mountain and praised Mount Meru. This aroused jealousy in Mount Vindhya and he started worshipping Lord Shiva. Lord Shiva granted him a boon to grow big, but also said that it should not obstruct anybody. Mount Vindhya grew by leaps and bounds, that it even obstructed the Sun and the Moon. The devotees then went to Lord Vishnu who in turn told them to approach Sage Agasthya. Sage Agasthya and his wife went to Mount Vindhya and requested him not to grow till they return from south. Mount Vindhya promised not to grow and sage Agasthya never returned back.
Lord Shiva blessed Mount Vindhya with a Jyotirlinga, which has been placed at Omkareshwar and has been eternally worshipped.