Vibhishana

Many of the references to Lanka in the Mahabharata are found in sage Markandeya's narration of the story of Rama and Sita to king Yudhishthira, which narration amounts to a truncated version of the Ramayana. The references in the following summary are to the Mahabharata, and adhere to the following form: (book:section). Markandeya's narration of the story begins at Book III (Varna Parva), Section 271 of the Mahabharata.

Sahadeva's expedition to South

The son of Pandu, viz. Sahadeva, conquered the town of Sanjayanti and the country of the Pashandas and the Karanatakas by means of his messengers alone, and made all of them pay tributes to him. The hero brought under his subjection and exacted tributes from the Paundrayas (Pandyas?) and the Dravidas along with the Udrakeralas and the Andhras and the Talavanas, the Kalingas and the Ushtrakarnikas, and also the delightful city of Atavi and that of the Yavanas. And, He having arrived at the seashore, then dispatched with great assurance messengers unto the illustrious Vibhishana, the grandson of Pulastya and the ruler of Lanka(2:30).

Ghatotkacha  
 

Vibheeshana is chiranjeevi and is still ruling Lanka ,as 5150 years ago when Rajsuya yagnya was performed by Yudhisthira , to conquer entire universe , even lanka had to be conquered , since Lord Rama had devised a boulder to prevent others/humans entering Lanka , Ghatotkacha son of Bheema goes aerially and asks Vibheeshana to accept superiority of Pandavas as an order from Krishna who is none other than Rama of tretayuga.

 

Presence of the King of Lanka in Yudhisthira's Rajasuya

Lanka king is listed as present in the conclave of kings present in Pandava king Yudhisthira's Rajasuya sacrifice.

.. The Vangas and Angas and Paundras and Odras and Cholas and Dravidas and Cheras and Pandyas and Mushika and Andhakas, and the chiefs of many islands and countries on the seaboard as also of frontier states, including the rulers of the Sinhalas, the barbarous mlecchas, the natives of Lanka, and all the kings of the West by hundreds, and all the chiefs of the seacoast, and the kings of the Pahlavas and the Daradas and the various tribes of the Kiratas and Yavanas and Sakrasand the Harahunas and Chinas and Tukharas and the Sindhavas and the Jagudas and the Ramathas and the Mundas and the inhabitants of the kingdom of women and the Tanganas and the Kekayas and the Malavas and the inhabitants of Kasmira ... (3:51).

Other fragmentary references

• Lanka, with its warriors, and horses, elephants and chariots (3:149).
• Lanka with its towers and ramparts and gates (3:147)
• The walls of Lanka (3:282).