It's said it was once 64 however only 12 where considering auspicious and holy and its likely that those 12 where taken better care of. It's not written as far as I found where the others have been located but it's clear they have been forgotten and decayed for the most. Hope this helps.
Hi Nehra, From what I have researched ,the 12 Jyotirlingas in India are considered sacred representations of the god Shiva. There are 12 of them because: They are mentioned in ancient Hindu texts called Puranas. They are spread across India, making them accessible to people from different regions. Each Jyotirlinga has a unique legend associated with Lord Shiva. They symbolize unity among diverse Hindu communities. The number 12 represents completeness and perfection.
The 12 Jyotirlingas are located in various regions of India, and they are:
Somnath in Gujarat
Mallikarjuna in Andhra Pradesh
Mahakaleshwar in Madhya Pradesh
Omkareshwar in Madhya Pradesh
Kedarnath in Uttarakhand
Bhimashankar in Maharashtra
Kashi Vishwanath in Uttar Pradesh
Trimbakeshwar in Maharashtra
Vaidyanath (Vaijnath) in Jharkhand
Nageshwar (Aundha Nagnath) in Gujarat
Rameshwar (Ramanathaswamy) in Tamil Nadu
Grishneshwar in Maharashtra