Haswell-Smith (2004) suggests that Rum is "probably" pre-Celtic, but may be Old Norse rõm-øy for "wide island" or Gaelic ì-dhruim (pronounced [iˈɣɾɯim]) meaning "isle of the ridge".

[9] In 1991 the Nature Conservancy Council of Scotland (the forerunner to NatureScot) reverted to the use of Rum without the h.[4][10][11] In the 13th century there may be references to the island as Raun-eyja and Raun-eyjum and Dean Munro writing in 1549 calls it Ronin.

[21] Geologically, Rùm is the core of a deeply eroded volcano that was active in the Paleogene period some 60 million years ago,[22] and which developed on a pre-existing structure of Torridonian sandstone and shales resting on Lewisian gneiss.

[23][24] Two of the Cuillin are classified as Corbetts: Askival and Ainshval, (Old Norse for "mountain of the ash trees" and "hill of the strongholds" respectively) and Rùm is the smallest Scottish island to have a summit above 762 metres (2,500 ft).

[25] Hallival and Askival are formed from an extraordinary series of layered igneous rocks created as olivine and feldspar crystals accumulated at the base of a magma chamber.

Lava flowing away from the volcanic centre formed Bloodstone Hill, gas bubbles leaving holes in the structure that were then filled with green agate flecked with red.

[33] As the climate became damper, peat expanded its coverage at the expense of woodland, and post-glacial sea level changes left raised beaches around the coastline 18–45 metres above the present sea-level, especially between Harris and A'Bhrideanach;[34] Bronze Age artefacts, such as barbed-and-tanged arrowheads typical of the Beaker People, have been found in the machair which replaced it[note 2].

[36] He wrote of Columba:Simple stone pillars, over 1.4 metres (4+1⁄2 feet) tall, have been found at Kilmory and Bàgh na h-Uamha ("bay of the cave"), and may date from this period.

A decade later, John put Amy, a faithful wife, aside to marry Princess Margaret, thus depriving his eldest son, Ranald, of the ability to inherit the lordship and those MacDonald lands.

[47] It is possible that during the early medieval period the island was used as a hunting reserve by the nobility;[48] in Gaelic it was referred to as Rìoghachd na Forraiste Fiadhaich — "the kingdom of the wild forest".

After a quick show trial of Godfrey's heir[49], and in view of Clan Ranald being no less responsible for the violence, King James killed Alexander MacGorrie and declared the Lordship of Garmoran forfeit.

Following the forfeiture, most of Garmoran remained with the Scottish crown until 1469, when James III granted Lairdship of it to John of Ross, the new MacDonald leader, who passed it to his own half-brother, Hugh of Sleat.

John Garbh (the youngest son) now obtained Rùm (possibly, Alexander had quitclaimed it to him); like Hugh's gains, Clan Ranald objected to this transfer.

A later report for the king indicated that the island was repopulated by members of Clan Ranald[55][56] The MacLeans of Rùm and of Duart were mild supporters of the Scottish reformation, remaining Episcopalian, rather than becoming Presbyterian, and consequently the Roman Catholic church thought them susceptible to re-conversion.

Half a century later, when visiting the wider region, Dr. Johnson was told that the laird[note 16] had hit one of the tenants across the back with a gold-tipped cane, as punishment for going to Roman Catholic mass, threatening the same treatment for any others who did so.

[61] Furthermore, the new demands on the land had reduced the great forest island into an essentially treeless landscape[note 17];[63] by the end of the century, this had caused the extinction of the native red deer (Cervus elaphus).

[69] Years later an eyewitness, a local shepherd, was more florid in his description of the events: "The people of the island were carried off in one mass, for ever, from the sea-girt spot where they were born and bred...

Ironically, in the words of one of the emigrees, Dr Lachlan, "the Curse and Scourge of the Highland Crofters" was now "much worse off than the comfortable people he turned out of Rùm 13 years previously".

In 1888, he decided to sell it; the sale prospectus described Rùm as "the most picturesque of the islands which lie off the west coast of Scotland" and "as a sporting estate it has at present few equals".

His heirs, however, felt that this was beneath his dignity, and demolished it, moving his sarcophagus into an elaborate mausoleum modelled as a Greek temple, built in 1892[75] and designed by William James Morley.

[76] Argyll, similarly, was not thought fitting for Rùm, and that same year[note 26] was moved by boundary review to the county of Inverness, where Eigg already sat.

Sir George died in France, in July 1939, shortly before the outbreak of World War II, and was interred in the family mausoleum on Rùm.

These migrating birds spend their winters in the South Atlantic off Brazil, and return to Rùm every summer to breed in burrows high in the Cuillin Hills.

Several rare upland species are found on the ultrabasic slopes of Barkeval, Hallival and Askival including the ground beetles Leistus montanus and Amara quenseli.

[92] A tree nursery was established at Kinloch in 1960 in order to support a substantial programme of re-introducing twenty native species including silver birch, hawthorn, rowan and holly.

[93] The forested area, which consists of over a million re-introduced native trees and shrubs, is essentially confined to the vicinity of Kinloch and the slopes near this site surrounding Loch Scresort and on nearby Meall á Ghoirtein.

The book told of a long-running scientific controversy over the alleged discovery of certain plants on Rùm by botanist John William Heslop-Harrison—discoveries that are now considered to be fraudulent.

[95] Rum has a number of national and international conservation designations for its spectacular natural and built heritage, including: The entire island is owned and managed as a single estate by NatureScot.

It reported to Mike Russell MSP the Minister for Environment in the Scottish Government, and in June a plan was announced to establish a locally-run trust with the aim of reintroducing crofting settlements to the area around Kinloch village.

[107] A Caledonian MacBrayne ferry, MV Lochnevis, links Rùm and the neighbouring Small Isles of Canna, Eigg and Muck, to the mainland port of Mallaig some 17 miles (27 kilometres) and 1⁄2 hours sailing time away.