Algernon St. Maur, 15th Duke of Somerset, etc. (22 July 1846 – 22 October 1923, in Maiden Bradley) was the son of Algernon St. Maur, 14th Duke of Somerset and Horatia Morler. He was also a baronet. On September 5, 1877, he married Susan Margaret Richards Mackinnon, the ninth daughter of Charles Mackinnon of Corriechatachan, but the marriage was childless. When Somerset died in 1923, he left no son, and his brothers Lord Ernest and Lord Edward had both recently died childless, so his titles and estates were inherited by the nearest heir, his distant cousin Colonel Edward Seymour.