Pataliputra, adjacent to modern-day Patna, Bihar, was a city in ancient India, originally built by Magadha ruler Ajatashatru in 490 BCE, as a small fort near the Ganges river. Udayin laid the foundation of the city of Pataliputra at the confluence of two rivers, the Son and the Ganges. He shifted his capital from Rajgriha to Pataliputra due to the latter's central location in the empire.

Patna, historically known as Pataliputra, is the capital and largest city of the state of Bihar in India. According to the United Nations, as of 2018, Patna had a population of 2.35 million, making it the 19th largest city in India. Covering 250 square kilometres (97 sq mi) and over 2.5 million people, its urban agglomeration is the 15th largest in India. Patna also serves as the seat of Patna High Court. The Buddhist, Hindu and Jain pilgrimage centres of Vaishali, Rajgir, Nalanda, Bodh Gaya and Pawapuri are nearby and Patna City is a sacred city for Sikhs as the tenth Sikh Guru, Guru Gobind Singh was born here. The modern city of Patna is mainly on the southern bank of the river Ganges. The city also straddles the rivers Sone, Gandak and Punpun. The city is approximately 35 kilometres (22 mi) in length and 16 to 18 kilometres wide.