Sixteen Mahajanapadas in Ancient India.

 Mahajanapadas (Sanskrit,: महाजनपद, Mahājanapadas) literally "Great Kingdoms" (from Maha, "great," and Janapada "foothold of a tribe," "country") refers to 16 monarchies and 'republics' that stretched across the Indo-Gangetic plains from modern-day Afghanistan to Bangladesh in the sixth century B.C.E., prior to and during the rise of Buddhism in India.

In ancient India, a number of kingdoms emerged during the Vedic Age that were spread across the Indo-Gangetic plain. These kingdoms were also called as republics and 16 of them were regarded the greatest of all. These 16 kingdoms were known as the 16 Mahajanapadas. These 16 Maha Janapadas are mentioned in the ancient literature and scriptures. The term Maha Janapada actually means "great country" and is derived from Sanskrit. The sixteen mahajanapadas rose before the start of Buddhism in India. Though these places were tribal settlements initially, roughly by 600 B.C they grew into bigger political entities by grabbing land. The sixteen mahajanapadas are given here in detail.

Kasi: The name Kasi was given to the tribe who settled around the Varanasi region. It’s a belief that the city got its name as Varanasi from the two rivers, Varuna and Asi, which surround the city. Before the rise of Buddha, among the sixteen Mahajanapadas, Kasi had a predominant position. After the rise of Buddha, the name Kasi of the tribes was converted into Kosala. In Matsya Puran, this place is named as Kausaka/Kausika. Lots of details about the Kasi can be known from the tales of Jatkas.
Kosala: It was located around 70 miles to north-west of the today’s Gorakhpur in Uttar Pradesh. It was surrounded by river Ganga from south, by the Himalayas from north, and by river Gandak from the east. Chief cities of Kosala were Sravasti, Ayodhya, and Saketa. Prasenjit was the ruler of Kosala Mahajanapadas and succeeded by his son Vidudahaba.
Kamboja: Kamboja was said to be located on the either side of the Hindukush. It is believed that originally they were located somewhere else. There are number of evidences from Asoka’s Edict no. XIII, Kautaliya’s Arthashasthra, and Mahabharata that Kamboja Mahajanapadas were republic peoples.
Gandhara: This kingdom was consisted of Gandharas who were masters in the art of wars. They are very much aggressive in nature. The Gandhara kingdom was founded by Gandhara, Aruddha’s son.
Avanti: Avanti was one of the most important kingdoms of 16 Mahajanapadas. It is founded in the India’s western part. Avanti is also one of the other important kingdoms of the 16 Mahajanapadas who initiated Buddhism. The whole Avanti kingdom was divided into two, the south and the north Avanti.
Assaka or Ashmaka: It was located in the southern part of India. The Assaka had its capital at Potali or Potana. It is believed that Ashmaka was located roughly at the place where present day Maharashtra is located.
Machcha: The kingdom of Machcha or Matsya was comprised the region of modern day Jaipur along with Bharatpur and Alwar in Rajasthan. King Virata was the founder of this Matsya kingdom and its capital named after him, Viratanagara. There are number of evidences show that this place was once ruled by Chedi.
Surasena: The kingdom Surasena was located in the west side of Yamuna River and Mathura was the capital of this kingdom. Avantiputra, one of the main disciples of Buddha, was the king of Surasena kingdom. He played the vital role in promoting the Buddhism during his kingdom.
Kuru: It has been said that Kuru belong to the Puru-Bharata family. These were known for their sound health and profound wisdom. Kuru, the son of Samvarsana, was the founder of Kururashtra in Kurukshetra.
Panchala: Panchala were located in the northern part of India. These were located between the river Ganga and the Himalayas ranges, where the present day Uttar Pradesh is located. Originally Panchala were monarchial but later on transformed into the republican form of government.
Chedi: Chedi were situated at two different places: one was mountainous regions of Nepal and the other was near Yamuna River. There is mentioning of Chedi in Rig Veda, which shows that Chedi kingdom is prevalent here since very long time.
Vatsa: The kingdom of Vatsa was situated roughly at the location of present day Allahabad in Uttar Pradesh. The capital of Vatsa was Kaushambi, which was a very prosperous city. The ruler of Vatsa was known as Udyana and Vatsa had a very powerful ruler, known as Udyana, adopted Buddhism as the religion in his kingdom.
Vajji: Vajji was an important center for political and cultural activities. It was located in northern part of India. The Vriji was comprised of nine allied races. Out of these nine races, the Vedehans, the Licchhavisthe, the Vajjis and the Jnatrikas were the important ones.
Malla: The Malla tribe was situated somewhere in the Eastern India. They had republic form of society and their territory consisted of nine provinces.
Anga: Anga kingdom is mentioned in the Atharva Veda and was situated roughly at the location of the modern day Bihar and West Bengal. River Champa was demarked as the line of separation from the Magadha. Anga was an important center of commerce and trade. It was considered as one of the chief cities of early India.
Magadha: The Magadhas are mentioned in the Atharva Veda. Magadha came into the spotlight under the king Bimbisara and his son Ajatasatru. The Magadha was situated roughly where the modern day Bihar is located.