Naimisha Forest or Naimiṣāraṇya was an ancient forest mentioned in the Mahabharata and the puranas. It lay on the banks of the Gomti River of Uttar Pradesh. It lay between the Panchala Kingdom and the Kosala Kingdom. The whole narration of Mahabharata took place at Naimisha Forest during a conclave of sages headed by the sage Saunaka, who gathered for a sacrifice to the cause of world peace. In this conclave Ugrasrava Sauti narrated the entire Mahabharata, the story of the great kings of Bharata dynasty to Saunaka. The central part of this story was the history of the Kauravas and Pandavas and their battle at Kurukshetra known as the Kurukshetra War.
In this forest, the famous Shaunaka rishi, who also wrote shlokas in praise of Shiva, chanted all the verses of the modern day Mahabharata, which was written by sage Ugrasravas Sauti, in one breath.
Earlier mention of Naimiṣa Forest is found in the Ramayana. The colophon of the yuddhakanda the Ramayana states that the twin sons of Rama, Kusha and Lava, narrated this epic in the Ashvamedha.