Nui is an atoll and one of nine districts of the Pacific Ocean state of Tuvalu. It has a land area of 3.37 km² and a population of 610. Traditionally Nuian culture is organised in three family circles - Tekaubaonga, Tekaunimala and Tekaunibiti families. Most people live on the western end of Fenua Tapu. In the 2012 census, 321 people live in Alamoni - Maiaki and 221 people live in Manutalake - Meang. The junior school is Vaipuna Primary School.
The biggest, most southern and most eastern island is Fenua Tapu, which is followed by Telikiai, Tokinivae, Pongalei, Talalolae, Pakantou, Unimai, Piliaieve and Motupuakaka.
The island was first sighted by Europeans on 16 January 1568 by Spanish navigator Álvaro de Mendaña, who named it Isla de Jesús because it was discovered on the day following the feast of the Holy Name. There are no less than six accounts of this event, that of Mendaña himself being as follows: "A little after nine o'clock in the morning, a lad called Trejo, being aloft, first sighted land upon the starboard side to the southwest...When we drew near, we found it so small that it was no more than six leagues in circumference. This island was very full of trees like palms; towards the north it had a reef, which entered the sea a quarter of a league, and towards the south was another smaller reef. On the west side it had a strand lying lengthways, with reefs in different parts. This is on the west side, for we could not go round the east side because of the weather. Taking this island from the sea outwards, it has the shape of two galleys, with a copse in the middle which appears like a fleet of ships" Mendaña found the island inhabited and five canoes came nearly within bow shot of his ship, when their occupants raised their paddles and turned back with shouts. Mendaña thereupon ordered signals to be made to them with a white cloth to try to get them to return, instead of which they landed and in turn stuck up signals along the shore. At night one of the ships showed a light, it was copied by a fire, and when it was put out the fire extinguished also. Hernán Gallego, Mendaña's pilot, says the natives were "naked and mulattoes" and Pedro Sarmiento de Gamboa, cosmographer in the expedition reported that the island "had a large fishery". As it was late Mendaña decided to defer landing until the morning and kept the ships tacking all night. With the dawn, however, a strong westerly storm blew up, and although they tried all day to regain the island they were at length compelled to give up. A Dutch expedition found Nui on the morning of June 14, 1825 and named the main island as Nederlandsch Eiland. The atoll has been called Egg or Netherland Island. The population of Nui from 1860–1900 is estimated to be between 250 and 300 people. Kirisome, was Nui's first and long serving pastor. Martin Kleis was the resident trader on Nui in the late 19th century who sold copra to Henderson and Macfarlane. The photographer Thomas Andrew visited Nui in about 1885–86. Nui Post Office opened around 1919 and a climate station was established in 1941. The traditional outrigger canoes from Nui were constructed with an indirect type of outrigger attachment and the hull is double-ended, with no distinct bow and stern. These canoes were designed to be sailed over the Nui lagoon. The booms of the outrigger are longer than those found in other designs of canoes from the other islands. This made the Nui canoe more stable when used with a sail than the other designs. Celebrations are held on Nui on the 16 February - Bogin te Ieka - to commemorate the Tsunami that struck the island on that day in 1882.
Nui was affected by storm surges caused by Cyclone Pam in early March 2015, which caused damage to houses, crops and infrastructure. On 22 March, 71 families of Nui remained displaced and were living in 3 evacuation centres or with other families. The Situation Report published on 30 March reported that Nui suffered the most damage of the three central islands ; with Nui suffering the loss of 90% of the crops. Health assessment teams visited Nui and the other islands affected by Cyclone Pam.
