Necker Island (Hawaii) in the context of "Papahānaumokuākea Marine National Monument"

The Polynesian Triangle is a region of the Pacific Ocean with three island groups at its corners: Hawaii (Hawaiʻi), Easter Island (Rapa Nui) and New Zealand (Aotearoa). This is often used as a simple way to define Polynesia.

Outside the triangle, there are traces of Polynesian settlement as far north as Necker Island (Mokumanamana), as far east as Salas y Gómez Island (Motu Motiro Hiva), and as far south as Enderby Island (Motu Maha). Also, there have once been Polynesian settlements on Norfolk Island and the Kermadec Islands (Rangitahua). By the time the Europeans first arrived, these islands were all uninhabited.

Nīhoa, also written Nihoa and also known as Bird Island or Moku Manu, is the tallest of ten islands and atolls in the uninhabited Northwestern Hawaiian Islands (NWHI). The island is located at the southern end of the NWHI chain, 296 km (160 nmi) southeast of Necker Island. Nīhoa is the closest NWHI in proximity to the eight main windward Hawaiian Islands at approximately 240 km (130 nmi) northwest of the island of Kauaʻi. The island has two peaks, 272 m (892 ft) Miller's Peak in the west, and 259 m (850 ft) Tanager Peak in the east. Nīhoa's area is about 171 acres (0.69 km) and is surrounded by a 142,000-acre (57,000 ha) coral reef. Its jagged outline gives the island its name, from Hawaiian nīhoa "toothed, serrated".

The island is home to 25 species of plants and several animals, making it the most diverse island in the entire NWHI. Endemic birds like the Nīhoa finch and Nīhoa millerbird, and endemic plants like Pritchardia remota and Schiedea verticillata are found only on Nīhoa. Amaranthus brownii was considered the rarest plant on Nīhoa and has not been directly observed on the island since 1983, and is now considered to be extinct. The plant communities and rocky outcrops provide nesting and perching areas for 18 species of seabirds, such as red-footed boobies and brown noddies, terns, shearwaters, and petrels. Prehistoric evidence indicates Native Hawaiians lived on or visited the island around AD 1000, but over time the location of Nīhoa was mostly forgotten, with only an oral legend preserving its name. Captain James Colnett rediscovered the island in 1788, and Queen Kaʻahumanu visited it in 1822. It was made part of the Kingdom of Hawaii by King Kamehameha IV.