Niue is a roughly oval, raised coral island that is about 40 miles (65 km) in circumference. The island has two distinct levels. The upper level, a central plateau with a maximum elevation of approximately 200 feet (60 metres), slopes steeply down at its edges to the lower level, a coastal terrace about 0.3 miles (0.5 km) wide and 80–90 feet (25–27 metres) high, which in turn slopes down to meet the sea in small cliffs. A fringing reef surrounds the island.

Precipitation on Niue averages about 80 inches (2,000 mm) annually and falls mostly during heavy rainstorms (sometimes including tropical cyclones (tropical cyclone)) from December to March. A devastating cyclone struck Niue in 2004, causing a number of deaths and substantial property damage in the coastal areas, including the capital. The wet season, which is humid and warm, lasts from November to March, and the cooler dry season from April to October.

The island's soil is extremely porous, so that water catchment from roofs is necessary to provide adequate water supply. The vegetation cover is scant but includes large trees, such as banyans and Tahiti chestnuts. There are also coconuts, fan palms, and pandanus, as well as hibiscus and other shrubs, ferns, and creepers.

The population is mostly Polynesian. English is widely spoken, and a large number of people speak both English and Niuean, a Polynesian language (Polynesian languages) akin to Tongan and Samoan; a small proportion speak only Niuean. The inhabitants are predominantly Christian. Most people live in villages on the fertile coastal strip, which is intensively cultivated. The population declined throughout the late 20th and early 21st centuries as many Niueans migrated to New Zealand because of limited economic prospects at home. In the early 21st century there were many times more native-born Niueans and their descendants living in New Zealand than on Niue itself.

Niue's currency is the New Zealand dollar. The economy is based mainly on agriculture. About one-fourth of the land is arable and is held in traditional family patterns; land ownership is passed down through family lines, and, by law, land cannot be sold to foreigners. Passion fruit, coconuts, pawpaw, and limes are cash crops. Subsistence crops include taro (locally called talo), yams, bananas, sugarcane, papaya, guava, and citrus fruits. Livestock includes pigs, chickens, and cattle, and fishing is conducted for domestic needs. The government has made the development of the fishing industry a priority, and a fish-processing plant was opened in the village of Amanau in 2004. About one-fifth of the land is forested. Manufacturing is centred on processing crops and includes lime juice, passion fruit, copra, honey, leather goods, and handicrafts for export. An industrial park was established in Fonuakula in the early 21st century. Tourism makes a growing contribution to the economy.

Alofi is the main port, and the island has a small airport as well. New Zealand is the major trading partner and source of financial aid. Continued financial assistance from New Zealand and international aid agencies, as well as remittances from relatives overseas, remain the key elements in maintaining a relatively high standard of living. The sale of postage stamps to philatelists and of fishing licenses as well as the provision of offshore banking services have also been important revenue sources.

Under the 1974 Niue Constitution Act, Niue is self-governing, though Niueans are New Zealand citizens and members of the Commonwealth. New Zealand is responsible for defense and external affairs as well as administrative and economic assistance as necessary. Executive authority is vested in the British monarch, represented by the governor-general of New Zealand. The leader of the government is the premier, elected by the 20-member Legislative Assembly. The members of the assembly are elected by universal adult suffrage; the legal voting age is 18. The majority of assembly members are elected from village constituencies; the rest are elected by all voters and serve as at-large members. The premier selects a cabinet from among the members of the assembly. A general election is held at least every three years, upon the dissolution of the Legislative Assembly at the request of the premier. Education is free and compulsory between ages 5 and 16. There is an extension centre of the University of the South Pacific at Alofi.

There is archaeological evidence that Niue was settled about 900 CE by Samoans. According to tradition, a second group, a war party from Tonga, arrived sometime in the 16th century. Capt. James Cook (Cook, James) landed on Niue in 1774 and, because of hostility from the Niueans, named it Savage Island. London Missionary Society members began to arrive in the 1830s, and by the 1850s the islanders had been converted to Christianity.

In 1900 Great Britain annexed Niue along with the western part of Samoa (the eastern part went to the United States). New Zealand annexed the island in 1901 as part of the Cook Islands, but in 1904 it was separated and given its own resident commissioner and island council. The first Niuean Legislative Assembly was elected in 1960, and in 1966 the resident commissioner's authority was partly delegated to the assembly and a Niuean leader of government was installed. In 1974 the people voted for a new constitution, choosing self-government in association with New Zealand. The devastation caused by a tropical cyclone in 2004 greatly affected the economy, and over the next few years the island began to rebuild with the help of foreign aid, particularly from the New Zealand government and the European Investment Bank. Niue is a member of the Secretariat of the Pacific Community (Pacific Community, Secretariat of the) and the Pacific Islands Forum.