The 16 Mahajanapadas are mentioned in the Buddhist text Angusadva Nikaya, Mahavastu and Jain text Bhagavati Sutra. Magadha was the most powerful of the sixteen Mahajanapadas, while Asmak (Ashmak) was the only mahajanpada situated on the banks of river Godavari in South India. While the rest had a monarchical system.

The first Magadha Empire was established in the sixth century, Bimbisara (about 544 -492 BC) ruler of the Harayak dynasty defeated Brahmadatta and established the Magadha Empire, ultimately he is considered the real founder of Magadha. Its ancient capital was Rajagriha. Later this capital was transferred to Pataliputra.

Ahichchhatra (present-day Bareilly) was the capital of Northern Panchal and Kampilya (Farrukhabad) was the capital of Southern Panchal.

Ajatashatru, the ruler of Magadha, killed his father Bimbasar for the ascension. Ajatashatru was also murdered by his son Udayin for his accession. Ajatashatru is also known as Kunik. During the reign of Ajatashatru, the first Buddhist council was organized in the Saptaparni cave of Rahgriha.

Mahapadmananda, the founder of the Nanda dynasty, is called Aporrashuram (the second incarnation of Parashurama) and Sarvakshatrantaka (destroyer of Kshatriyas) in the Puranas. While Mahabodhivansh is called Ugrasena. After the Sheshnag dynasty of Magadh, the Nanda dynasty (344 -329 BC) was established. He became the most powerful ruler of Magadha. The peremptory ruler and Ekarat were his other achievements. Kharvel's Hathigumpha inscription describes his Kalinga conquest.

The Shakya of Kapilavastu, the Lichchavi of Vaishali, the Bhaggas of Sunsumaragiri, the Koliyas of Rama Village, the Mallas of Kushinara, the Videhas of Mithila, etc. are republic in the Ganga Valley. Shursen Mahajanapada was the famous janpada of North-India with its capital at Mathura.

Among the 16 Mahajanapadas, Ashmak or Assak, which was situated between the Narmada and Godavari rivers of South India, had its capital at Paithan or Potan or Potli (ancient name). Potan and Potli belong to Andhra Pradesh. Ashmak was a monarchical state, founded by an Ikshvaku dynastic ruler.

The Mahajanapadas are described in Buddhist and Jain texts. Malwa Mahajanapada (present Madhya Pradesh) was known as Avantika in ancient times. This state was divided into two parts. The capital of the northern Avanti was Ujjayini and the capital of the southern Avanti was Mahishmati. According to the Buddhist text Mahavagga Jataka, Chand Pradyot dynasty rule in Avanti.

The famous Naimisharanya shrine is located on the banks of the Gomti River in Sitapur district of Uttar Pradesh. A fair is organized here on Somavati Amavasya. According to mythological beliefs, here 88,000 sages did penance together. It is also mentioned in the Mahabharata as a dense forest. Maharishi Dadhichi's ashram is located near this place called Mishrikh.

Gandhar Taxila, the great center for learning, was the capital of Gandhara.