Overlooking the town of Stornoway (Western Isles), across the Inner Harbour, Lews Castle was built in 1847-54 as a country house for Sir James Matheson (1796 - 1878), occupying the site of a lodge which had been the seat of the Mackenzies of Seaforth. An impressive A-listed three-storey Tudoresque fort, complete with towers and battlements, the architect was Charles Wilson (1810-63) and the work cost £60,000. Matheson had made his fortune in the opium trade in the Far East and bought the island of Lewis in 1844, which he was to run from this house. The surrounding by woodland policies were created from rough grazing land and involved the clearing of tenants and the re-routing of public roads. A conservatory complex was added in 1875 but this fell into disrepair during World War II.
Soap baron, William Lever, Lord Leverhulme (1851 -1925), bought the castle, along with the island, in 1918. He extended the building and added modern conveniences such as central heating, electric lighting and telephones connecting various parts of the house. In 1923, he gifted 25,900 ha (64,000 acres) land, including the castle and its policies to the people of Lewis to be managed by the Stornoway Trust. Used as a naval hospital during World War II, Lews Castle was sold to Ross & Cromarty Country Council and became Lews Castle College in 1953. When the college moved to a modern building in the grounds in the 1970s, the castle became home to Lews Castle School. In 1988, the school was forced to evacuate the building due to structural problems.
The castle is owned by the Western Isles Council (Comhairle nan Eilean Siar) and was converted to become the home of the Museum Nan Eilean in 2016, with a large rear extension built to house its archive. The grounds are open to the public.