The Castle was built for Sir (then simply Mr) George Bullough in the last years of the 19th and first years of the 20th centuries and completed around 1901. George Bullough inherited the Island of Rum on his father's death in 1891. He also inherited a share in the family business, the textile machinery manufacturers Howard and Bullough of Accrington. The building used by John Bullough and his family while on Rum, the White House, was not sufficient for George's needs and was reputed to be rat infested. George's half brother Ion had inherited the considerable estate of Meggernie which includes a magnificent and ancient castle. Could this be why George wanted a castle?
The date stone reads 1897 but this marks the start of the build. The architects were the firm of Leeming and Leeming of London whose other commissions included the Admiralty in London and the Municipal Buildings in Edinburgh. It is of steel frame construction clad with red sandstone which was obtained from Corrie Quarry on Arran. The stone was shipped in on those classic west coast of Scotland work-horses, the "puffer". Arran stone was used because the local stone was not suitable for the fine detailing required.
It is said that Sir George wanted to build the castle the same length as his steam yacht, the Rhouma, which measured 221ft. The story goes that the final design could "only" be 150 ft due to two streams running down to the sea obstructing the site. However, an examination of the site shows that it could easily have accommodated the larger length so the final design was more likely to be aesthetic. The castle has a colonnaded veranda on three sides which was originally roofed with glass. A large glass conservatory, which no longer survives, was constructed on the south side with direct access from the drawing room.
It was first occupied not by the owner but by convalescent soldiers from the Boer War, sent by George Bullough to finish their recuperation on Rum.