The British Nationality Act 1981 reclassified Saint Helena and the other Crown colonies as British Dependent Territories. The islanders lost their right of abode in Britain. For the next 20 years, many could find only low-paid work with the island government, and the only available employment outside Saint Helena was on the Falkland Islands and Ascension Island. The Development and Economic Planning Department (which still operates) was formed in 1988 to contribute to raising the living standards of the people of Saint Helena.

In 1989, Prince Andrew launched the replacement RMS St Helena to serve the island; the vessel was specially built for the Cardiff–Cape Town route and featured a mixed cargo/passenger layout.This service ended in January 2018, as the fastest and easiest access to St Helena is via the airport, with it's first commercial flight being made in 2017.

Under the provisions of the 1833 India Act, control of Saint Helena passed from the East India Company to the British Crown, and it became a crown colony. Subsequent administrative cost-cutting triggered a long-term population decline: those who could afford to do so tended to leave the island for better opportunities elsewhere. The latter half of the 19th century saw the advent of steamships not reliant on trade winds, as well as the diversion of Far East trade away from the traditional South Atlantic shipping lanes to a route via the Red Sea (which, prior to the building of the Suez Canal, involved a short overland section). So the number of ships calling at the island fell from 1,100 in 1855 to only 288 in 1889.

In 1840, a British naval station established to suppress the African slave trade was based on the island, and between 1840 and 1849 over 15,000 freed slaves, known as "Liberated Africans", were landed there.

After Napoleon's death, the thousands of temporary visitors were withdrawn and the East India Company resumed full control of Saint Helena. Between 1815 and 1830, the EIC made the packet schooner St Helena available to the government of the island, which made multiple trips per year between the island and the Cape, carrying passengers both ways and supplies of wine and provisions back to the island.

Napoleon praised Saint Helena's coffee during his exile on the island, and the product enjoyed a brief popularity in Paris in the years after his death.

In 1815, the British government selected Saint Helena as the place of detention for Napoleon Bonaparte. He was taken to the island in October 1815. Britain also took the precaution of sending a garrison of soldiers, with an experienced officer (Edward Nicolls), to uninhabited Ascension Island, which lay between St. Helena and Europe.

Napoleon stayed at the Briars pavilion on the grounds of the Balcombe family's home until his permanent residence at Longwood House was completed in December 1815. Napoleon died there on 5 May 1821

In 1657, Oliver Cromwell granted the English East India Company a charter to govern Saint Helena and, the following year, the company decided to fortify the island and colonise it with planters. The long tradition that the early settlers included many who had lost their home in the 1666 Great Fire of London has been shown to be a myth. The first governor, Captain John Dutton, arrived in 1659, making Saint Helena one of Britain's earliest colonies outside North America and the Caribbean. A fort and houses were built. After the Restoration of the English monarchy in 1660, the East India Company received a royal charter giving it the sole right to fortify and colonise the island. The fort was renamed James Fort and the town Jamestown, in honour of the Duke of York, later King James II of England.

Between January and May 1673, the Dutch East India Company forcibly took the island, before English reinforcements restored English East India Company control. The company experienced difficulty attracting new immigrants, and sentiments of unrest and rebellion arose among the inhabitants. Ecological problems of deforestation, soil erosion, vermin and drought led Governor Isaac Pyke in 1715 to suggest that the population be moved to Mauritius, but this was not acted upon and the company continued to subsidise the community because of the island's strategic location. A census in 1723 recorded 1,110 people, including 610 slaves.

Most historical accounts state that the island was sighted on 21 May 1502 by Galician navigator João da Nova sailing in the service of Portugal, and that he named it Santa Helena after Helena of Constantinople. A paper published in 2015 observes that 21 May is probably a Protestant rather than a Catholic or Orthodox feast day, and the date was first quoted in 1596 by Jan Huyghen van Linschoten, who was probably mistaken because the island was discovered several decades before the Reformation and the start of Protestantism. An alternative discovery date of 3 May is suggested as being historically more credible; it is the Catholic feast day of the finding of the True Cross by Saint Helena in Jerusalem, and cited by Odoardo Duarte Lopes and Sir Thomas Herbert.

Another theory holds that the island found by da Nova was actually Tristan da Cunha, 2,430 kilometres (1,510 mi) to the south, and that Saint Helena was discovered by some of the ships attached to the squadron of the Estêvão da Gama expedition on 30 July 1503 (as reported in the account of clerk Thomé Lopes). Thomé Lopes mapped St Helena's geographic position with reasonable accuracy when he quoted its distance and direction with respect to locations such as Ascension, Cape Verde, São Tomé and the Cape of Good Hope. The island's map location with respect to Ascension and the Cape of Good Hope was likewise described following the 1505 Portuguese expedition led by Francisco de Almeida.

Two hundred years ago today, on October 15, 1815, Napoleon arrived on the island of Saint Helena where he was exiled for the rest of his life.

1. Saint Helena is in the South Atlantic, 2,500 miles east of Brazil, 1,200 miles west of Africa. It covers an area of just 47 square miles.