There is a considerable difference of opinion today among the scholars over the identification of Kalinganagara, the reputed capital of Kalingadesa. Almost all the copper-plate grants of the Ganga kings of Kalinga were issued from their capital, Kalinganagara. There is two sites Mukhalingam and Kalingapatna, let us see the arguments
Kalinganagara is to be identified with the present site of Mukhalingam or the joint site of Mukhalingam and Nagarakatakam, situated on the bank of the Vamsadhara and at a distance of about 30 miles from the sea. This identification has been arrived from the evidence of some dedicatory inscriptions found in the temple of God Madhukesvara. The inscriptions differently refer to a 'Nagara' of Kalinga, not Kalinganagara. The passages occurring in the inscriptions are: Kalingavani Nagare, Kalinga-Desa- Nagare, Nagare Madhukesvarayam (the word 'Kalinga' omitted).
The copper-plate inscription of Anantavarman,dated 1040 of an unspecified era, edited by Fleet records the fact that Kamanava II, the nephew of Kamarnava I, had a town named "Nagara," in which he built a lofty temple for an emblem of God Isa in the linga form to which he had given the name of "Madhukesa" because it was produced by a Madhuka tree. The temple still exists at Mukhalingam. The inscription further informs us that Kamarnava I, the alleged founder of the Ganga dynasty, had for his capital the town named Jantavuram. Jantavuram = Jayantapuram = Madhukesvaram = Mukhalingam.
However this is a far fetched theory.
An inscription found in the temple of Mukhalingesvara, which records a grant to the dancers and musicians of the God Madhukesvara issued from Kalinganagara itself by Anantavarman "From Kalinganagara" is to be interpreted as "in Kalinganagara." , "Svasti! Srimat Kalinganagarat! etc." meaning "Hail! From the Victorious Kalinganagara." Thus, when there is a record concerning the dancers and musicians of the temple of Madhukesvara in Kalinganagara, issued from and inscribed in a prominent place in the temple itself, in Kalinganagara, what stronger proof is required to identify Mukhalingam and Nagarakatakam with the ancient Kalinganagara?"
But this is just a guess work.
The famous Hathigumpha Inscription of Kharavela. King Kharavela clearly mentions in his inscription that just afterhis coronation, in the first year of his reign, he repaired his capital Kalinganagara, of which the gates, city-walls and buildings had been destroyed by storm (Vata-vihata- Gopura-pakara-nivesanampati-Samkharayati Kalinga-Nagaram). The storm which felled down the strong royal gate, city-walls (i.e., fort-walls) and buildings, must have been a violent one. This undoubtedly proves the metropolitan city being situated on the sea-side as such furious hurricanes are only commonly experienced in seaporttowns on the east-coast.
Kalidasa in Raghu Vamsa says, Indumati's Svayamvara, Sunanda, her companion, took the royal princes to the king of Kalinga, named Hemangada and described him as the ruler of a kingdom of which the Mahendra Hill and the sea were the two natural boundaries. The place is described as being just on the sea-beach. "......The sea itself, the waves of which are seen from the windows of his palace, and the deep resounding roars of which surpass the sound of the watch-drum being close at hand, awakes him as it were, when slept in his palace-room. Sport, O Princess, with this king on the sea-shore, where the palm-trees grove make a rustling noise. This is a clear proof of the sea- side capital of the king kalinga as kalidasa knew it.
The Dasakumara-Carita, (the Kalinga capital has been mentioned as Kalinganagara. Mention is made of the Kalinga-Raja named Karddana, as amusing himself with his friends and family in a sportive party on the sea-beach.
The reference to Kalinga in the Mahabharata is equally illuminating. Arjuna entering the Kalinga-gate (Kalinga- Rastra-Dvara) came to the sea-side. Thence, returning, he went to the Mahendra Hill.
Pliny Wrote "To the south, the territory of the Calinga extended as far as the promontory of Calingon and the town Dandagula which is said to be 625 Roman miles (or 524 British miles) from the mouth of the Ganges." This is exactly where kalinga nagara is.
The copperplate inscriptions of the Gangeya Kings. We read in the Achyutapuram grant of Indravarman (Raja-Simha,) the Chicacole plates of Devendravarman, the Parlakemdi grant of Indravarman, the Parlakemidi plates of the time of Vajrahasta , the Alamanda plates of Ananta-arman, the Vizagapatam copper-plate grant of Devendra arman, the victorious Kalinga-nagara (the issuing place of the charter) is regularly described as Sarvartu-ramaniya or Sarvarthu-Sukha-ramaniya, i.e., pleasant in all seasons. This passage is of importance as emphatically calling our attention to the pleasant and temperate climate of the capital as held by the Gangeya Kings. What other place except Kalingapatam, by its name and moderate climate can satisfy this condition?
In Sanskrit the words Nagara, Pattana, and Pura are synonymous. No Sanskrit dictionary nor a book of literature can say anything on this point to the contrary. According to some authorities, however, a nagara means a large town in the midst of 800 villages and a pattana is a place, where a king with his retinue resides.
Further lot of artifact have been found at kalingapatana to prove that it has ancient history.