Tonga is the island nation whose historic capital, Nuku'alofa, is famous for New Year's Eve celebrations.
Nuku'alofa is the capital of Tonga, an island country in the South Pacific. Tonga's position near the International Date Line has made it prominent in discussions of places that welcome the new year very early. News reports and travel coverage have frequently highlighted celebrations in and around the capital.
Tonga's time-zone history has changed over time, and the exact order in which Pacific countries reach midnight depends on their current legal time settings. That makes it important not to treat old “first country” lists as permanently accurate.
The answer is Tonga, while Nuku'alofa is the city. Samoa and Fiji are also Pacific island countries with major New Year's traditions, but they are separate states and should not be substituted for Tonga.