Algernon Borthwick, 1st Baron Glenesk JP (27 December 1830 – 24 November 1908), known as Sir Algernon Borthwick, Bt, between 1887 and 1895, was a British journalist and Conservative politician. He was the owner of the Morning Post (which merged with The Daily Telegraph in 1937).
Borthwick was the son of Peter Borthwick, editor of the Post, and Margaret, daughter of John Colville, of Ewart, Northumberland. He was sent to King's College School.
Borthwick started his career in 1852 as the newspaper's Paris correspondent. He took over as editor when his father died, and in 1876 became proprietor. Known as a conservative voice in the politics of the time, he was elected MP for Kensington South in 1885 and became an ally of Lord Randolph Churchill. He was knighted in 1880 and created a Baronet, of Piccadilly in the Parish of St George, Hanover Square, in the County of Middlesex, in 1887. On his retirement from the House of Commons in 1895 he was raised to the peerage as Baron Glenesk, of Glenesk in the County of Midlothian.
Lord Glenesk married Alice Beatrice Lister (d. 1898) on 5 April 1870. She was the daughter of the writers Thomas Henry Lister and his wife Lady Maria Theresa Villiers, daughter of George Villiers. They had two children:
Lord Glenesk died in November 1908, aged 77, when the title became extinct. Glenesk was interred in the Glenesk Mausoleum in East Finchley Cemetery. The mausoleum had been designed and built for Glenesk by Arthur Blomfield in 1899, and also held the remains of his wife, and his son, Oliver. The mausoleum was later listed Grade II on the National Heritage List for England.