[2] It is the fifth-largest loch by surface area in Scotland, at 26.7 km2 (10.3 sq mi), and the deepest freshwater body in the British Isles with a maximum depth of 310 m (1,017 ft).

[7] The water of the loch is clear and oligotrophic, with a minimal intake of nutrients, making it a Site of Special Scientific Interest (SSSI).

[16] The same island was briefly the location first of a Mass stone and then of an illegal and clandestine Catholic minor seminary founded by Bishop James Gordon, until the Jacobite rising of 1715 forced its closure and eventual reopening at Scalan in Glenlivet.

[18] According to Strathglass historian Flora Forbes, however, "a Catholic chapel at this time anywhere throughout the Highlands was usually a barn-like structure, with no windows and a mud floor.

[20] According to a later report for the Duke of Newcastle, "Upon their arrival at the lake, they immediately spread themselves opposite to the Isle, and in full view of the rebels thereon; who, concluding themselves quite free from danger, fired on our people, at the same time calling them by insulting and opprobrious names, being near enough to be heard.

This exultation, however, was quickly at an end; for the King's ships having sailed round to that part of the coast where their boats had little more than a mile to be carried overland to the lake... the rebels immediately lost all courage..."[21] Although the Bishop and the Jacobite leaders managed to quickly row from Eilean Bàn to the loch shore and "escaped into the mountains", according the same report for the Duke of Newcastle, when the government soldiers and sailors arrived upon Eilean Bàn, "They found the before-named Popish bishop's house and chapel; which the sailors quickly gutted and demolished, merrily adorning themselves with the spoils of the chapel.

Watts has termed the 8 June 1746 book burning and the destruction of most of Bishop MacDonald personal papers, "an irreplaceable loss both for the eighteenth-century Church and the scholar of today.

In 1917, Dom Odo Blundell of Fort Augustus Abbey wrote, "At Morar chapel-house is preserved a set of green vestments, with red and white intermingled, bearing the date 1745.

The same remarks apply to the old chalice, which bears the inscription, Ad usum Pr Fr Vincenti Mariani, Missri Scot.

John Fergussone suspected "that Lord Lovat's lameness must have rendered it utterly impracticable for him to travel in so rugged a country", and the crew of HMS Furnace accordingly continued meticulously searching inside the caves surrounding the Loch, "for three days and nights".

[20][25] In his naval history of the Jacobite rising and its aftermath, historian John S. Gibson commented about the capture of Lord Lovat at Loch Morar, "London, which, with the events of the past year, had come to abhor highlanders, could scarcely have been more elated had Charles Edward himself been caught.

A small mythology was quick to grow up about the circumstances of his capture, as in the contemporary print of Fergussone and the soldiers of Guise's bursting in on the aged peer disguised as an old woman.

Swordland Lodge, on the northern shore of the loch, was used as training school STS 23b by the Special Operations Executive during the Second World War.

[35] An outwash fan made up of sand and gravels at the western end of the loch marks the limit of the re-advance in the Morar valley.

[38] Subsequently, colonised by vegetation and known as Mointeach Mhòr (the mossy plain), these deposits blocked the outflow of the loch to the south, so that it drained from the north-west corner instead.