Sixteen Great Kingdom or Solah Mahajanapads consist of Panchala, Machcha, Surasena, Assaka, Avanti, Anga, Kosala, Kashi, Magadha, Vajji, Malla, Chedi, Vatsa, Kuru, Gandhara and Kamboja.
By 600 BC, the nomadic Vedic Aryan settled down in the form of tribes forming kingdoms along the plains of river Ganga (Ganges). Many of these 16 mahajanapadas converted into bigger tribes and kingdoms.
Panchala: Located in what is present day Uttar Pradesh, this province extended from Himalayas in the north to Ganges in south. The state was mainly a monarchy but changed to a republic by the end of 5th century BC.
Machcha: It was a part of Chedi province but got its independence. The capital of the province was Viratnagar in the name of the ruler of Matsya/Machcha ‘Virat’. The province is located where we have Jaipur and Bharatpur today.
Surasena: Had its capital Mathura, a holy place of Hindus and birth place of Lord Krishna. Ironically the major population of Surasena province was Hindu but the king Avantiputra was a prime disciple of Lord Buddha, thus he played a critical role in spreading Buddhism in this province.
Assaka: Located in the central part of India, this province was on the bank of River Godavari (present day Maharashtra)
Avanti: A very important kingdom was one of the four most important monarchial kingdoms of all sixteen Mahajanapadas. It was located where we have present day Madhya Pradesh. Avanti was annexed by Magadha by 4 century BC. Avanti was a prime center of Buddhist teachings.
Anga: This was close to Magadha, present day Bihar and parts of West Bengal. It had great terms and trade relations with other Mahajanapadas. It was one of the most flourishing province of ancient India.
Kosala: City of Ayodhya was a part of this province. Kosala was surrounded by Himalayas in the north, Ganges in the South and river Gandhak in the East. In the later years Kosala was annexed into the kingdom of Magadha. Famous kings were Prasenjit and his son, Vidhudabha.
Kashi: The religious hub of all the sixteen mahajanapadas, Kasi was the most powerful province before Buddhism evolved, later with the influence of Buddhism, the religious hub shifted to neighboring province of Kosala.
Magadha: Considered to be one of the most important states during 2nd and 3rd century BC, Magadha had nothing much to boast about during the 6th century BC. The only prominent ruler was Ajatashatru and his father Bimbsara. Magadha is located where we have present day Bihar.
Vajji: The Lichchavis, the Vedehans, the Jnatrikas and the Vajjis were the most important races living in Vajji Samaj. The Lichchavis had their capital in Vaishali which was a religious place for Buddhists at in that era. Vajji was conquered by Magadha in the reign of Ajatashatru.
Malla: The main religions of this state were Jainism and Buddhism. The most important provinces were Kusinara and Pawapuri. Buddha took his last meal in Kusinara. Pawapuri is still one of the important pilgrimages of Jains.
Chedi: One of the oldest Mahajanapada, Chedi or Cheti has its mention in the Rig Veda. The province was divided into two parts, the one in Nepal and the other stretching from the bank of river Yamuna to the bank of river Narmada.
Kuru: One of the earliest republic of India, Kuru was a land of wisdom. The people were known for their good health. Originally founded somewhere near Kurukshetra, it spread in Himalayas in the north and a part of it settled in central India.
Vatsa: Liberated from the province of Kuru, Vatsa is present day Allahabad. The king Udyana was a follower of Buddhism and helped spreading Buddhism in this state. The capital city was Kaushambi, which was one of the most powerful cities of that era. Vatsa was a dream destination for merchants and dwellers in those days.
Gandhara: Truly Vedic in nature Gandhara were the masters of warfare. They were aggressive by nature. They established themselves on the banks of Indus to the banks of river Kumba. In the late 5th century BC the kingdom expanded to parts of Punjab.
Kamboja: Kamboja were a mixed race of Iranians and Indians. The tribe was located on both sides of Hindukush Mountains. The province of Kamboja is supposed to have trade terms with Gandharas who were located to the south of them.