Odra was a kingdom located in the northern Odisha in Eastern India. This kingdom was mentioned in the epic Mahabharata. Odras were neighbours to the Vangas. It is believed that the Odia language and the state Odisha got their names derived from the name "Odra".
Only a single reference of Odra is found in Mahabharata. The Odras were mentioned along with the Vangas, Angas and Paundras as bringing tribute for Yudhishthira for his Rajasuya sacrifice (3,51).
There is a mysterious mention of the name Udrakeralas in Mahabharata. It is not known if the word Udra in the composite word Udra-Keralas has any relations with Odra. The name Oriya originated from Odra. The Bhagbata Purana mentions Odra, among the six sons of Dirghatamas by queen Sudesna with the Pundrakas, Dravidas, Kambojas, Sakas, Yavanas etc. Pliny placed Oretes near mountain Mallus which can be identified with Malayagiri near Pallahara in the present Angul district. Prof B.C Majumdar observs ".. the hilly country lying between Kalinga and Dakshina Kosala was the Odra land." R.D Banerji calls the Odras as the people of Northern Orissa. In the early medieval period, Odra became a distinct territorial division. The earliest reference to Odra in this period is gleaned from the Soro Copper Plates of Somadatta. It mentions the northern Tosali was a part of Odravisaya. By that time, Northern Tosali was a fairly extensive territory comprising Midnapur and undivided Balasore district and a considerable portion of Mayurbhanj and undivided Cuttack districts. Its inclusion in Odra indicates that the latter was a vast region between river suvarnarekha in the north & Vaitarani in the south.
Odra finds mention in Hiuen Tsang's
Si-Yu-Ki where he describes it as Wu-Cha which was 1400 miles in circuit. Other historians opine that Odra comprised undivided Midnapur, Balasore, Cuttack, Ganjam & Puri districts . However, the present day research excludes the possibility of the inclusion of Puri in Odra. It is only because Che-li-ta-Lo, a port mentioned by Hieun Tsang and its location at Puri by Cunningham and others have been challenged by scholars who locate it either in Tirtol (Jagatsinghpur district), Chandabali (Bhadrak district) or Manikapatana (On the bank of Chilika lake in Ganjam district) .
As noticed Odra, Utkala, Kalinga, Kongoda, Tosali & Kosala were territories having distinct boundaries of their own and the boundary changed from time to time in ancient and early medieval days. Sometimes, it is noticed that some of these names were used as interchangeable terms, e.g.- Odra was known as Tosali during Bhauma-karas . At the advent of fifteenth century A.D poet Sarala dasa made udisa as Orissa synonymous with Odra rastra which became Odisha rajya during Gajapatis. Right from the days of Kapilendradeva (1435-1467 A.D), this empire land of the oriya speaking people has been known as Odisha.
Reference-^ HISTORY OF ODISHA BY HARIHAR PANDA (Professor & Head, Department of History National Defence Academy, Pune. Former Reader, Department of History, Ravenshaw University, Cuttack.)