Which region was known as the Mahajanapada of Magadha in the 6th Century B.C.?

Magadha was an ancient Indian kingdom in southern Bihar, and was counted as one of the sixteen Mahajanapadas, 'Great Kingdoms' of ancient India. Magadha played an important role in the development of Jainism and Buddhism, and two of India's greatest empires, the Maurya Empire and Gupta Empire, originated in Magadha.