Lord Jagannatha is a form of Lord Vishnu. Jagannatha is typically understood as a manifestation of Vishnu or his avatar, Krishna. He is worshipped with his brother Balabhadra and sister Subhadra. The Jagannatha triad are usually worshipped on a raised platform in the temple's inner sanctum.
The famous Jagannatha Temple in Puri, Odisha, India, is dedicated to this form of Lord Krishna and is one of the Char Dham pilgrimage sites in Hinduism.