The places named directly or indirectly in the Rig Veda can be classified into five basic geographical regions, from west to east, on the basis of present-day terminology: Afghanistan, Punjab, Haryana, Uttar Pradesh and Bihar. Amongst these, Uttar Pradesh of the present-day is more or less equivalent to the land known in ancient literature as Aryavarta or Madhyadesa. Neither the word Aryavarta, nor the word Madhyadesa, is found in the Rig Veda. Nor is there any direct reference in the hymns to any place in Uttar Pradesh. But, the hymns IX.96 and X.179.2 composed by a Bharata Rishi who attributed his compositions to his remote ancestor, Pratardana present an important mention. Pratardana was a king of KASI, which is in eastern Uttar Pradesh. This can only mean that the Bharata Kings of the early period of the Rig Veda were Kings of KASI and, in the light of the other information in the Rig Veda, the land of the Bharatas extended from KASI in the east to Kurukshetra in the west. (This description has been given by Shrikant G. Talageri in his historical analysis of Rig Veda.)
This means that, essentially Uttar Pradesh is what Bharat is referred to in the primary Vedic and Hindu scripture Rig Veda and not the whole of India from north to South.