The Hebrides are the source of much of Scottish Gaelic literature and Gaelic music. Today the economy of the islands is dependent on crofting, fishing, tourism, the oil industry, and renewable energy. The Hebrides have lower biodiversity than mainland Britain, but there is a significant presence of seals and seabirds.
The Hebrides have a diverse geology ranging in age from Precambrian strata that are amongst the oldest rocks in Europe to Paleogene igneous intrusions.
The Hebrides can be divided into two main groups, separated from one another by the Minch to the north and the Sea of the Hebrides to the south. The Inner Hebrides lie closer to mainland Scotland and include Islay, Jura, Skye, Mull, Raasay, Staffa and the Small Isles. There are 36 inhabited islands in this group. The Outer Hebrides are a chain of more than 100 islands and small skerries located about 70 kilometres (43 mi) west of mainland Scotland. There are 15 inhabited islands in this archipelago. The main islands include Barra, Benbecula, Berneray, Harris, Lewis, North Uist, South Uist, and St Kilda. In total, the islands have an area of approximately 7,200 square kilometres (2,800 sq mi) and a population of 44,759.
A complication is that there are various descriptions of the scope of the Hebrides. The Collins Encyclopedia of Scotland describes the Inner Hebrides as lying "east of the Minch", which would include any and all offshore islands. There are various islands that lie in the sea lochs such as Eilean Bàn and Eilean Donan that might not ordinarily be described as "Hebridean", but no formal definitions exist.
In the past, the Outer Hebrides were often referred to as the Long Isle (Scottish Gaelic: An t-Eilean Fada). Today, they are also known as the Western Isles, although this phrase can also be used to refer to the Hebrides in general.
The Hebrides have a cool temperate climate that is remarkably mild and steady for such a northerly latitude, due to the influence of the Gulf Stream. In the Outer Hebrides the average temperature for the year is 6 °C (44 °F) in January and 14 °C (57 °F) in summer. The average annual rainfall in Lewis is 1,100 millimetres (43 in) and sunshine hours range from 1,100 – 1,200 per annum. The summer days are relatively long, and May to August is the driest period.
The Hebrides were settled during the Mesolithic era around 6500 BC or earlier, after the climatic conditions improved enough to sustain human settlement. Occupation at a site on Rùm is dated to 8590 ±95 uncorrected radiocarbon years BP, which is amongst the oldest evidence of occupation in Scotland. There are many examples of structures from the Neolithic period, the finest example being the standing stones at Callanish, dating to the 3rd millennium BC. Cladh Hallan, a Bronze Age settlement on South Uist is the only site in the UK where prehistoric mummies have been found.
In 55 BC, the Greek historian Diodorus Siculus wrote that there was an island called Hyperborea (which means "beyond the North Wind"), where a round temple stood from which the moon appeared only a little distance above the earth every 19 years. This may have been a reference to the stone circle at Callanish.
A traveller called Demetrius of Tarsus related to Plutarch the tale of an expedition to the west coast of Scotland in or shortly before AD 83. He stated it was a gloomy journey amongst uninhabited islands, but he had visited one which was the retreat of holy men. He mentioned neither the druids nor the name of the island.
The first written records of native life begin in the 6th century AD, when the founding of the kingdom of Dál Riata took place. This encompassed roughly what is now Argyll and Bute and Lochaber in Scotland and County Antrim in Ireland. The figure of Columba looms large in any history of Dál Riata, and his founding of a monastery on Iona ensured that the kingdom would be of great importance in the spread of Christianity in northern Britain. However, Iona was far from unique. Lismore in the territory of the Cenél Loairn, was sufficiently important for the death of its abbots to be recorded with some frequency and many smaller sites, such as on Eigg, Hinba, and Tiree, are known from the annals.
North of Dál Riata, the Inner and Outer Hebrides were nominally under Pictish control, although the historical record is sparse. Hunter (2000) states that in relation to King Bridei I of the Picts in the sixth century: "As for Shetland, Orkney, Skye and the Western Isles, their inhabitants, most of whom appear to have been Pictish in culture and speech at this time, are likely to have regarded Bridei as a fairly distant presence.”
Viking raids began on Scottish shores towards the end of the 8th century and the Hebrides came under Norse control and settlement during the ensuing decades, especially following the success of Harald Fairhair at the Battle of Hafrsfjord in 872. In the Western Isles Ketill Flatnose may have been the dominant figure of the mid 9th century, by which time he had amassed a substantial island realm and made a variety of alliances with other Norse leaders. These princelings nominally owed allegiance to the Norwegian crown, although in practice the latter's control was fairly limited. Norse control of the Hebrides was formalised in 1098 when Edgar of Scotland formally signed the islands over to Magnus III of Norway. The Scottish acceptance of Magnus III as King of the Isles came after the Norwegian king had conquered Orkney, the Hebrides and the Isle of Man in a swift campaign earlier the same year, directed against the local Norwegian leaders of the various island petty kingdoms. By capturing the islands Magnus imposed a more direct royal control, although at a price. His skald Bjorn Cripplehand recorded that in Lewis "fire played high in the heaven" as "flame spouted from the houses" and that in the Uists "the king dyed his sword red in blood".
The Hebrides were now part of the Kingdom of the Isles, whose rulers were themselves vassals of the Kings of Norway. This situation lasted until the partitioning of the Western Isles in 1156, at which time the Outer Hebrides remained under Norwegian control while the Inner Hebrides broke out under Somerled, the Norse-Gael kinsman of the Manx royal house.
Following the ill-fated 1263 expedition of Haakon IV of Norway, the Outer Hebrides and the Isle of Man were yielded to the Kingdom of Scotland as a result of the 1266 Treaty of Perth. Although their contribution to the islands can still be found in personal and place names, the archaeological record of the Norse period is very limited. The best known find is the Lewis chessmen, which date from the mid 12th century.
As the Norse era drew to a close, the Norse-speaking princes were gradually replaced by Gaelic-speaking clan chiefs including the MacLeods of Lewis and Harris, Clan Donald and MacNeil of Barra. This transition did little to relieve the islands of internecine strife although by the early 14th century the MacDonald Lords of the Isles, based on Islay, were in theory these chiefs' feudal superiors and managed to exert some control.
The Lords of the Isles ruled the Inner Hebrides as well as part of the Western Highlands as subjects of the King of Scots until John MacDonald, fourth Lord of the Isles, squandered the family's powerful position. A rebellion by his nephew, Alexander of Lochalsh provoked an exasperated James IV to forfeit the family's lands in 1493.
In 1598, King James VI authorised some "Gentleman Adventurers" from Fife to civilise the "most barbarous Isle of Lewis". Initially successful, the colonists were driven out by local forces commanded by Murdoch and Neil MacLeod, who based their forces on Bearasaigh in Loch Ròg. The colonists tried again in 1605 with the same result, but a third attempt in 1607 was more successful and in due course Stornoway became a Burgh of Barony. By this time, Lewis was held by the Mackenzies of Kintail (later the Earls of Seaforth), who pursued a more enlightened approach, investing in fishing in particular. The Seaforths' royalist inclinations led to Lewis becoming garrisoned during the Wars of the Three Kingdoms by Cromwell's troops, who destroyed the old castle in Stornoway.
With the implementation of the Treaty of Union in 1707, the Hebrides became part of the new Kingdom of Great Britain, but the clans' loyalties to a distant monarch were not strong. A considerable number of islesmen "came out" in support of the Jacobite Earl of Mar in the "15" and again in the 1745 rising including Macleod of Dunvegan and MacLea of Lismore. The aftermath of the decisive Battle of Culloden, which effectively ended Jacobite hopes of a Stuart restoration, was widely felt. The British government's strategy was to estrange the clan chiefs from their kinsmen and turn their descendants into English-speaking landlords whose main concern was the revenues their estates brought rather than the welfare of those who lived on them. This may have brought peace to the islands, but in the following century it came at a terrible price. In the wake of the rebellion, the clan system was broken up and islands of the Hebrides became a series of landed estates.
The early 19th century was a time of improvement and population growth. Roads and quays were built; the slate industry became a significant employer on Easdale and surrounding islands; and the construction of the Crinan and Caledonian canals and other engineering works such as Telford's "Bridge across the Atlantic" improved transport and access. However, in the mid-19th century, the inhabitants of many parts of the Hebrides were devastated by the clearances, which destroyed communities throughout the Highlands and Islands as the human populations were evicted and replaced with sheep farms. The position was exacerbated by the failure of the islands' kelp industry that thrived from the 18th century until the end of the Napoleonic Wars in 1815 and large scale emigration became endemic.
As Iain mac Fhearchair, a Gaelic poet from South Uist, wrote for his countrymen who were obliged to leave the Hebrides in the late 18th century, emigration was the only alternative to "sinking into slavery" as the Gaels had been unfairly dispossessed by rapacious landlords. In the 1880s, the "Battle of the Braes" involved a demonstration against unfair land regulation and eviction, stimulating the calling of the Napier Commission. Disturbances continued until the passing of the 1886 Crofters' Act.
For those who remained, new economic opportunities emerged through the export of cattle, commercial fishing and tourism. Nonetheless emigration and military service became the choice of many and the archipelago's populations continued to dwindle throughout the late 19th century and for much of the 20th century. Lengthy periods of continuous occupation notwithstanding, many of the smaller islands were abandoned.
There were, however, continuing gradual economic improvements, among the most visible of which was the replacement of the traditional thatched blackhouse with accommodation of a more modern design and with the assistance of Highlands and Islands Enterprise many of the islands' populations have begun to increase after decades of decline. The discovery of substantial deposits of North Sea oil in 1965 and the renewables sector have contributed to a degree of economic stability in recent decades. For example, the Arnish yard has had a chequered history but has been a significant employer in both the oil and renewables industries.
The widespread immigration of mainlanders, particularly non-Gaelic speakers, has been a subject of controversy.
Many contemporary Gaelic musicians have roots in the Hebrides, including Julie Fowlis (North Uist), Catherine-Ann MacPhee (Barra), Kathleen MacInnes (South Uist), and Ishbel MacAskill (Lewis). All of these singers have repertoire based on the Hebridean tradition, such as puirt à beul and òrain luaidh (waulking songs). This tradition includes many songs composed by little-known or anonymous poets before 1800, such as "Fear a' bhàta," "Ailein duinn," and "Alasdair mhic Cholla Ghasda." Several of Runrig's songs are inspired by the archipelago; Calum and Ruaraidh Dòmhnallach were raised on North Uist and Donnie Munro on Skye. Singer-songwriter Janet Noade used the Outer Hebrides' deep sense of isolation as the theme for her song "Hebrides" (2017) which deals with her personal illness. The video for the song, remixed and titled "Hebrides (Rockall Mix)" can be found on youtube. 
The Gaelic poet Alasdair mac Mhaighstir Alasdair spent much of his life in the Hebrides and often referred to them in his poetry, including in An Airce and Birlinn Chlann Raghnaill. The best known Gaelic poet of her era, Màiri Mhòr nan Òran (Mary MacPherson, 1821–98), embodied the spirit of the land agitation of the 1870s and 1880s. This, and her powerful evocation of the Hebrides—she was from Skye—has made her among the most enduring Gaelic poets. Allan MacDonald (1859–1905), who spent his adult life on Eriskay and South Uist, composed hymns and verse in honour of the Blessed Virgin, the Christ Child, and the Eucharist. In his secular poetry, MacDonald praised the beauty of Eriskay and its people. In his verse drama, Parlamaid nan Cailleach (The Old Wives' Parliament), he lampooned the gossiping of his female parishioners and local marriage customs.
In the 20th century, Murdo Macfarlane of Lewis wrote Cànan nan Gàidheal, a well-known poem about the Gaelic revival in the Outer Hebrides. Sorley MacLean, the most respected 20th-century Gaelic writer, was born and raised on Raasay, where he set his best known poem, Hallaig, about the devastating effect of the Highland Clearances. Aonghas Phàdraig Caimbeul, described by MacLean as "one of the few really significant living poets in Scotland, writing in any language" (West Highland Free Press, October 1992), and whose Scottish Gaelic-language novel, An Oidhche Mus do Sheòl Sinn, was voted in the Top Ten of the 100 Best-Ever Books from Scotland, was raised on South Uist.
The area around the Inaccessible Pinnacle of Sgurr Dearg of Skye provided the setting for the Scottish Gaelic feature film Seachd: The Inaccessible Pinnacle (2006). The script was written by the actor, novelist, and poet Aonghas Phàdraig Chaimbeul, who also starred in the movie.
An Drochaid, an hourlong documentary in Scottish Gaelic, was made for BBC Alba documenting the battle to remove tolls from the Skye bridge.
J.M. Barrie's Marie Rose contains references to Harris inspired by a holiday visit to Amhuinnsuidhe Castle and he wrote a screenplay for the 1924 film adaptation of Peter Pan whilst on Eilean Shona. The Hebrides, also known as Fingal's Cave, is a famous overture composed by Felix Mendelssohn while residing on these islands, while Granville Bantock composed the Hebridean Symphony. Enya's song "Ebudæ" from Shepherd Moons is named for the Hebrides (see below). The 1973 British horror film The Wicker Man is set on the fictional Hebridean island of Summerisle. The experimental first-person adventure video game Dear Esther takes place on an unnamed Hebridean island. The 2011 British romantic comedy "The Decoy Bride" is set on the fictional Hebrides island of Hegg.
The video game "The Other 99" is set in a fictional area in the Hebridean islands. The game was released on 25 August 2016 on Steam Early Access.
Gallowmere, the main setting of MediEvil is said to be located in the Hebrides as stated in its sequel game, Medievil 2.
The residents of the Hebrides have spoken a variety of different languages during the long period of human occupation.
It is assumed that Pictish must once have predominated in the northern Inner Hebrides and Outer Hebrides. The Scottish Gaelic language arrived via Ireland due to the growing influence of the kingdom of Dál Riata from the 6th century AD onwards, and became the dominant language of the southern Hebrides at that time. For a few centuries, the military might of the Gall-Ghàidheil meant that Old Norse was prevalent in the Hebrides. North of Ardnamurchan, the place names that existed prior to the 9th century have been all but obliterated. The Old Norse name for the Hebrides during the Viking occupation was Suðreyjar, which means "Southern Isles"; in contrast to the Norðreyjar, or "Northern Isles" of Orkney and Shetland.
South of Ardnamurchan, Gaelic place names are more common, and after the 13th century, Gaelic became the main language of the entire Hebridean archipelago. Due to Scots and English being favoured in government and the educational system, the Hebrides have been in a state of diglossia since at least the 17th century. The Highland Clearances of the 19th century accelerated the language shift away from Scottish Gaelic, as did increased migration and the continuing lower status of Gaelic speakers. Nevertheless, as late as the end of the 19th century, there were significant populations of monolingual Gaelic speakers, and the Hebrides still contain the highest percentages of Gaelic speakers in Scotland. This is especially true of the Outer Hebrides, where a slim majority speak the language. The Scottish Gaelic college, Sabhal Mòr Ostaig, is based on Skye and Islay.
Ironically, given the status of the Western Isles as the last Gaelic-speaking stronghold in Scotland, the Gaelic language name for the islands – Innse Gall – means "isles of the foreigners"; from the time when they were under Norse colonisation.
The earliest written references that have survived relating to the islands were made by Pliny the Elder in his Natural History, where he states that there are 30 Hebudes, and makes a separate reference to Dumna, which Watson (1926) concludes is unequivocally the Outer Hebrides. Writing about 80 years later, in 140-150 AD, Ptolemy, drawing on the earlier naval expeditions of Agricola, writes that there are five Ebudes (possibly meaning the Inner Hebrides) and Dumna. Later texts in classical Latin, by writers such as Solinus, use the forms Hebudes and Hæbudes.
The name Ebudes recorded by Ptolemy may be pre-Celtic. Islay is Ptolemy's Epidion, the use of the "p" hinting at a Brythonic or Pictish tribal name, Epidii, although the root is not Gaelic. Woolf (2012) has suggested that Ebudes may be "an Irish attempt to reproduce the word Epidii phonetically rather than by translating it" and that the tribe's name may come from the root epos meaning "horse". Watson (1926) also notes the possible relationship between Ebudes and the ancient Irish Ulaid tribal name Ibdaig and the personal name of a king Iubdán recorded in the Silva Gadelica.
The names of other individual islands reflect their complex linguistic history. The majority are Norse or Gaelic but the roots of several other Hebrides may have a pre-Celtic origin. Adomnán, the 7th century abbot of Iona, records Colonsay as Colosus and Tiree as Ethica, both of which may be pre-Celtic names. The etymology of Skye is complex and may also include a pre-Celtic root. Lewis is Ljoðhús in Old Norse and although various suggestions have been made as to a Norse meaning (such as "song house") the name is not of Gaelic origin and the Norse credentials are questionable.
The earliest comprehensive written list of Hebridean island names was undertaken by Donald Monro in 1549, which in some cases also provides the earliest written form of the island name. The derivations of all of the inhabited islands of the Hebrides and some of the larger uninhabited ones are listed below.
Lewis and Harris is the largest island in Scotland and the third largest in the British Isles, after Great Britain and Ireland. It incorporates Lewis in the north and Harris in the south, both of which are frequently referred to as individual islands, although they are joined by a land border. Remarkably, the island does not have a common name in either English or Gaelic and is referred to as "Lewis and Harris", "Lewis with Harris", "Harris with Lewis" etc. For this reason it is treated as two separate islands below. The derivation of Lewis may be pre-Celtic (see above) and the origin of Harris is no less problematic. In the Ravenna Cosmography, Erimon may refer to Harris (or possibly the Outer Hebrides as a whole). This word may derive from the Ancient Greek erimos meaning "desert". The origin of Uist (Old Norse: Ívist) is similarly unclear.
There are various examples of Inner Hebridean island names that were originally Gaelic but have become completely replaced. For example, Adomnán records Sainea, Elena, Ommon and Oideacha in the Inner Hebrides, which names must have passed out of usage in the Norse era and whose locations are not clear. One of the complexities is that an island may have had a Celtic name, that was replaced by a similar-sounding Norse name, but then reverted to an essentially Gaelic name with a Norse "øy" or "ey" ending. See for example Rona below.
The names of uninhabited islands follow the same general patterns as the inhabited islands. The following are the ten largest in the Hebrides and their outliers.
The etymology of St Kilda, a small archipelago west of the Outer Hebrides, and its main island Hirta is very complex. No saint is known by the name of Kilda and various theories have been proposed for the word's origin, which dates from the late 16th century. Haswell-Smith (2004) notes that the full name "St Kilda" first appears on a Dutch map dated 1666, and that it may have been derived from Norse sunt kelda ("sweet wellwater") or from a mistaken Dutch assumption that the spring Tobar Childa was dedicated to a saint. (Tobar Childa is a tautological placename, consisting of the Gaelic and Norse words for well, i.e. "well well"). The origin of the Gaelic for "Hirta"—Hiort, Hirt, or Irt—which long pre-dates the use of "St Kilda", is similarly open to interpretation. Watson (1926) offers the Old Irish hirt, a word meaning "death", possibly relating to the dangerous seas. Maclean (1977), drawing on an Icelandic saga describing an early 13th-century voyage to Ireland that mentions a visit to the islands of Hirtir, speculates that the shape of Hirta resembles a stag, hirtir being "stags" in Norse.
The etymology of small islands may be no less complex. In relation to Dubh Artach, R. L. Stevenson believed that "black and dismal" was a translation of the name, noting that "as usual, in Gaelic, it is not the only one."
In some respects the Hebrides lack biodiversity in comparison to mainland Britain; for example, there are only half as many mammalian species. However, these islands provide breeding grounds for many important seabird species including the world's largest colony of northern gannets. Avian life includes the corncrake, red-throated diver, rock dove, kittiwake, tystie, Atlantic puffin, goldeneye, golden eagle and white-tailed sea eagle. The last named was re-introduced to Rùm in 1975 and has successfully spread to various neighbouring islands, including Mull. There is a small population of red-billed chough concentrated on the islands of Islay and Colonsay.
Red deer are common on the hills and the grey seal and common seal are present around the coasts of Scotland. Colonies of seals are found on Oronsay and the Treshnish Isles. The rich freshwater streams contain brown trout, Atlantic salmon and water shrew. Offshore, minke whales, Killer whales, basking sharks, porpoises and dolphins are among the sealife that can be seen.
Heather moor containing ling, bell heather, cross-leaved heath, bog myrtle and fescues is abundant and there is a diversity of Arctic and alpine plants including Alpine pearlwort and mossy cyphal.
Loch Druidibeg on South Uist is a national nature reserve owned and managed by Scottish Natural Heritage. The reserve covers 1,677 hectares across the whole range of local habitats. Over 200 species of flowering plants have been recorded on the reserve, some of which are nationally scarce. South Uist is considered the best place in the UK for the aquatic plant slender naiad, which is a European Protected Species.
Hedgehogs are not native to the Outer Hebrides—they were introduced in the 1970s to reduce garden pests—and their spread poses a threat to the eggs of ground nesting wading birds. In 2003, Scottish Natural Heritage undertook culls of hedgehogs in the area although these were halted in 2007 due to protests; trapped animals were instead relocated to the mainland.