In ancient India it was the capital of the VatsaMahajanapada, one of 16 such regions. The Puranas state that Vatsa was named after a Kaśī king. The Ramayana and the Mahabharata attribute the credit of founding its capital Kauśāmbī to a Chedi prince Kuśa or Kuśāmba. The Puranas state that after the washing away of Hastinapura by the Ganges, the Bhāratas king Nicakṣu, great-great grandson of Janamejaya, abandoned the city and settled in Kauśāmbī. This is supported by the Svapnavāsavadattā and the Pratijñā-Yaugandharāyaṇa attributed to Bhāsa. Both of them have described the king Udayana as a scion of the Bhāratas family (Bhārata-kula). The Puranas provide a list of Nicakṣu’s successors which ends with king Kṣemaka.Gautama Buddha visited Kaushambi several times during the reign of Udayana on his effort to spread the dharma, the Noble Eightfold Path and the Four Noble Truths. Udayana was a Buddhistupāsaka. The Chinese translation of the Buddhist canonical text Ekottara Āgama states that the first image of Buddha, carved out of sandalwood was made under the instruction of Udayana.According to the Puranas, the 4 successors of Udayana were Vahināra, DanḍapāṇI, Niramitra and Kṣemaka. Later, Vatsa was annexed by Avanti. Maniprabha, the great-grandson of Pradyota, ruled at Kauśāmbī as a prince of Avanti.Ashoka gave importance to Kaushambi and placed a pillar of Ashoka in Kaushambi, which has inscriptions there in Pali. A Jainaderasar was also constructed in Kaushambi. Both the pillar and the temple still exist there and the ruins of Vatsa and its university are still being excavated by archaeologists.Kaushambi is also the birthplace of sixth Jain Tirthankar Padam Prabhu Ji.
Kaushambi is a newly created district out of Allahabad. It consists of major towns such as Chail, Manjhanpur, Bharwari, Kashia Muratganj, Sirathu, Karari and Kara.It is very easy to reach Kaushambi by road; it is approximately 45 km from Allahabad. This site is good for history lovers who have interest in ancient history. Many Kaushambi artifacts are in Allahabad Museum. It has a few excavated sites, including a Pillar of Ashoka with inscriptions in Pali; surrounding the pillar is a historic site of ruins of the VatsaMahajanapada and its university.There is a Jainderasar 14 km from Sarai Akil. The soil is very fertile and it is world-famous for the Surkha mango. The Surkha region lies mainly in Allahabad.