Tambapanni is the district in Sri Lanka where

Prince Vijaya According to the ''Mahāvaṃsa'' chronicle, Prince Vijaya (c. 543–505 BCE) was the first Sinhalese king. Legends and records from both Indian and Sri Lanka sources say that he along with several hundred followers came to Sinhala after they ...

landed after leaving Supparaka. Later on the capital was founded in Tambapanni and following that the whole island came to bear the same name.

References

Populated places in Northern Province, Sri Lanka Former capitals of Sri Lanka Pre Anuradhapura period {{NorthernLK-geo-stub