According to Bhagavata Purana, Krishna was born without a sexual union, but by divine "mental transmission" from the mind of Vasudeva into the womb of Devaki. Based on scriptural details and astrological calculations the date of Krishna's birth, known as Janmashtami, is 19 July 3228 BCE and departed on 3102 BCE. Krishna belonged to the Vrishni clan of Yadavas from Mathura, and was the eighth son born to the princess Devaki, and her husband Vasudeva.
Mathura (in present day Mathura district, Uttar Pradesh) was the capital of the Yadavas, to which Krishna's parents Vasudeva and Devaki belonged. King Kansa, Devaki's brother, had ascended the throne by imprisoning his father, King Ugrasena. Afraid of a prophecy from a divine voice from the heavens that predicted his death at the hands of Devaki's eighth "garbha", Kansa had the couple locked into a prison cell. After Kansa killed the first six children, Devaki apparently had a miscarriage of the seventh. However in reality, the womb was actually transferred to Rohini secretly. This was how Balarama, Krishna's elder brother was born. Once again Devaki became pregnant. Now due to the miscarriage, Kamsa was in a puzzle regarding 'The Eighth One' but his ministers advised that the divine voice from the heavens emphasised "the eight garbha" and so this is the one. That night Krishna was born in the Rohini nakshatra and simultaneously Goddess Durga was born as Yogamaya in Gokulam to Nanda and Yashoda.
Since Vasudeva knew Krishna's life was in danger, Krishna was secretly taken out of the prison cell to be raised by his foster parents, Yasoda  and Nanda, in Gokula (in present day Mathura district). Two of his other siblings also survived, Balarama (Devaki's seventh child, transferred to the womb of Rohini, Vasudeva's first wife) and Subhadra (daughter of Vasudeva and Rohini, born much later than Balarama and Krishna).