The following passage from Wikipedia says that
The Vidarbha kingdom in the Sanskrit epic Mahabharata is among the many kingdoms ruled by Yadu kings (Bhoja Yadavas). It is the southernmost kingdom within the epic's geographical horizon, south of the Vindhyarange, in the region still known as Vidarbha in what is now Central India.
How can it be proved? Are there any mentions to the actual geographical location of Vidarbha in scriptures?
