A province of Sri Lanka, identified with the modern Jaffna peninsula and the north west of Sri Lanka.
The Buddha’s second visit to Sri Lanka was to Nāgadīpa, to settle a dispute between two Nāgā, Mahodara and Cūḷodara (Mhv.i.47).
Jambukola (q.v.) was a harbour in Nāgadīpa, and there a vihāra was built by Devānampiyatissa (Ibid., xx.25) and later restored by Kaniṭṭha-
Another vihāra, called Sālipabbata, was built by Mahallaka Nāga (Ibid.,xxxv.124). The Unnalomaghara, the Rājāyatana dhātucetiya and the Amalacetiya were probably all places of worship in Nāgadīpa (Cv.xlii.62).
The Valāhakassa Jātaka (J.ii.128) says that the coast of Sri Lanka, from the river Kalyāṇī to Nāgadīpa, was once infested by yakkhiṇis. Once (J.iii.187) Nāgadīpa was known as Serumadīpa, and nearby was Karadīpa, earlier known as Ahidīpa (J.iv.238).
An old story, given in the Commentaries (e.g., VibhA.444), speaks of a king called Dīparāgā, who reigned over Nāgadīpa in great splendour. Nāgadīpa was once an important centre of Buddhism in Sri Lanka (e.g., ibid., 446, 467; AA.i.422. MA.i.545; see also J.R.A.S., vol. xxvi) and contained many places of pilgrimage. There is a legend (DA.iii.899; VibhA.433), which relates that, when the Buddha’s dispensation (sāsana) comes to an end, all the Buddha’s relics in Sri Lanka will gather together at the Mahācetiya and travel to the Rājāyatana-
According to the Rasavāhinī (ii.19) the place was so called because it was given as gift to the woman named Nāgā. See Nāgā (7).