The Babylonians are often credited with the earliest recorded New Year festival, called Akitu.
Akitu was a major Mesopotamian festival associated with the renewal of kingship, the agricultural cycle, and the god Marduk. In Babylon, it was connected with the beginning of the year in the month of Nisanu, which occurred in spring rather than on January 1.
The festival included processions, religious rites, and the public reaffirmation of the king's role. Its ceremonies were linked to the wider religious and political structure of ancient Babylon rather than to a modern midnight countdown.
Calling it the “first” New Year celebration requires care: earlier peoples may have marked seasonal or calendrical renewals without leaving comparable written records. Akitu is described as one of the earliest documented New Year festivals, not necessarily the first celebration humans ever held.