Brahma, Vishnu and Shiva are in the form of mountains in Braj

Brahma, Vishnu and Shiva are in the form of mountains in Braj

In Barsana, Lord Brahma assumed the form of mountain. The mountain is called “Brahm Parvat”. 
Lord Vishnu assumed the form of mountain in “Vilas Garh”, which is located in Barsana as well. The mountain is called “Vishnu Parvat”.
There is a separate narrow lane called “Sankari Gali” which links both of these mountains, where the famous “Daan Leela” of Lord Krishn took place.
Lord Shiva assumed the form of mountain in Nandgaun. The mountain is called “Shiv Parvat”.

Yatraaham Parvato Bhuyabalakrishnasute Namah.
Nandaghaatrisametastvam Mamopari Viraajate.
- Padma Purana

Translation: (Padma Purana)
“Lord Shiva assumed the form of a mountain at Nandgaon, Braj. Lord Shiva requested Yashoda Maiya to dwell with Lord Krishn and Lord Balrama over him.”

Ath Vrishabhanupurotpatti Mahatmy Varnanam Varahe Padme Ch: -
Puraakritaganasyaante Brahmana Parthito Harih.
Mamopari Sada Tvamhi Raaskreedam Karishyasi.
Sarvabhirbrajgopibhih Pravritkaale Kritaarthakrit.

At the end of Satya Yuga, Lord Brahma requested Lord Krishn to dwell with all the gopis over Him. So Lord Krishn said to Brahma Ji: “You should go to Barsana and assume the form of mountain there. I will give you leela darshan there.”

There is also one famous Katha related to it, when Tridev [Brahma, Vishnu, Shiva] wanted to take test of Sati Anusuiya, then Sati cursed Brahma, Vishnu, and Shiva that you have behaved very indefinitely, so go, become mountains, then all three Gods became mountains and their name became Trik.