Not unlike the Isles of Scilly it is possible that Ceann Iar, Shivinish and Ceann Ear formed a single body of land within historic times, and that their land area has greatly decreased due to overgrazing, sea inundation, and wind erosion.

Smaller islands in the group include Deasker (Deas-Sgeir), Shillay (Siolaigh) and Stocaigh (or Stockay).

The 28 ft (8.5 m) motorised open wooden boat was built circa 1932 for the last family to leave the Monach Islands, and had lain unused at Lochmaddy before being rescued by the local history society.

[7] Jacobite sympathiser James Erskine, Lord Grange (1679–1754), had his wife Rachel kidnapped and abandoned on the Monach Isles between 1732 and 1734.

When Lady Grange complained about her condition, she was told by her host that he had no orders to provide her either with clothes, or food other than the normal fare he and his wife were used to.

[14][1][15] The International Union for Conservation of Nature (IUCN) classifies as the islands (via the SSSI designation) as meeting the criteria for a Category IV protected area.

[16] The SAC designation extends to cover the seas surrounding the group,[15] and in 2014 a larger area of the sea surrounding the islands (in total 6,200 hectares or 18 square nautical miles) was declared a Nature Conservation Marine Protected Area (NCMPA).