Mandhata is a holy hill located on the banks of the Narmada river in Khandwa district of Madhya Pradesh. Mandhata, also called Shivapuri or Omkareshwar.  The hill lies at a distance of about 12 miles from Mortakka. The hill is of great religious importance, as one of the 12 revered Jyotirlinga shrines of Shiva is located here. There are two temples, namely, Omkareshwar and Amareshwar, which are attractive. Here the Narmada river flows around the hill in the shape of an ‘Om’.

The word Omkar is literally the enunciation of OM or the OM sound. The soft stone with which the temple was constructed has lent its pliable surface to a rare degree of detailed work, of which the frieze figures on the upper portion are the most striking. Omkareshwar is a holy town situated at a distance of 77 km from Indore. It derives its name from the sacred Hindu symbol of Om.

The place is a pilgrimage site, as there are a number of Hindu temples and Jain temples located here. It is basically an island, in the shape of Om, on the confluence of the rivers Narmada and Kaveri. The island is divided into north and south by a deep gully and is linked by a bridge. A boat ride in the Narmada river around the island of Omkareshwar is quite enjoyable.The devotees kneel before the Jyotirlinga to be blessed by it. Omkareshwar presents a magnificent blend of natural as well as human artistry.

Source:

https://en.wikipedia.org/wiki/Mandhata

https://timesofindia.indiatimes.com/travel/destinations/omkareshwar-madhya-pradesh/ps46918777.cms

https://www.india9.com/i9show/Mandhata-Hill-55759.htm