Markandeya is an ancient rishi (sage) from the Hindu tradition, born in the clan of Bhrigu Rishi.
He is celebrated as a devotee of both Shiva and Vishnu and is mentioned in a number of stories from the Puranas.
The Markandeya Purana especially, comprises a dialogue between Markandeya and a sage called Jaimini, and a number of chapters in the Bhagavata Purana are dedicated to his conversations and prayers.
He is also mentioned in the Mahabharata. Markandeya is venerated within all mainstream Hindu traditions.
Today, Markandeya Tirtha, where the sage Markandeya wrote the Markandeya Purana is situated on a trekking route to the Yamunotri Shrine in the Uttarkashi district, Uttarakhand.