Krishna Janmashtami lit. ”Occasion of the birth of Krishna”, also known simply as Janmashtami or Gokulashtami, is an annual Hindu festival that celebrates the birth of Krishna, the eighth avatar of Vishnu.
It is an important festival, particularly in the Vaishnavism tradition of Hinduism. Dance-drama enactments of the life of Krishna according to the Bhagavata Purana (such as Rasa Lila or Krishna Lila), devotional singing through the midnight when Krishna was born, fasting (upavasa), a night vigil (Ratri Jagaran), and a festival (Mahotsav) on the following day are a part of the Janmashtami celebrations.
It is celebrated particularly in Mathura and Vrindavan, along with major Vaishnava and non-sectarian communities found in Manipur, Assam, Bihar, West Bengal, Odisha, Madhya Pradesh, Rajasthan, Gujarat, Maharashtra, Karnataka, Kerala, Andhra Pradesh, Tamil Nadu and all the other states of India.
Krishna Janmashtami is followed by the festival Nandotsava, which celebrates the occasion when Nanda distributed gifts to the community in honor of the birth.
-Wikipedia