Personal life
On 31 July 1860, Horsley Beresford was married to Catharine Anne Dent (died 1941), the second daughter of Cmdr. William Dent of Shortflatt Tower and the former Ellen Mary Kerr (a daughter of Andrew Seton Kerr). Together, they were the parents of:
Hon. Caroline Catherine Horsley-Beresford (1861–1929), who married Col. George Alexander Eason Wilkinson of Middlethorpe Hall and Dringhouse Manor, in 1886.
Hon. Louisa Horsley-Beresford (1863–1866), who died young.
William Marcus de la Poer Horsley Beresford, 4th Baron Decies (1865–1910), who married Maria Gertrude Willoughby, a daughter of Sir John Willoughby, 4th Baronet, and sister to Maj. Sir John Willoughby, Bt.
John Graham Hope Horsley de la Poer Beresford, 5th Baron Decies (1866–1944), aide-de-camp to the Prince Arthur, Duke of Connaught who married Helen Vivien Gould, a daughter of railroad executive George Jay Gould I, in 1911. After her death in 1931, he married Elizabeth Wharton Drexel (widow of Harry Lehr) in 1936.
Hon. Seton Robert de la Poer Horsley Beresford (1868–1928), who married actress Delia Dorothy O'Sullivan, a daughter of Daniel John O'Sullivan, in 1899. They divorced in 1909 and he married Joan Rosemary Graves-Sawle, eldest daughter and coheiress of Rear Admiral Sir Charles John Graves-Sawle, 4th Baronet, in 1915.
Hon. Catherine Elizabeth Ellen Horsley Beresford (1870–1948), who married Lt.-Col. Edward J. M. Lumb, in 1902.
Hon. Charlotte Ernestine Horsley-Beresford (1871–1923), who married Maj. Cameron Barclay, fourth son of Henry Ford Barclay (and brother to Charles Barclay and Sir George Barclay), in 1892.
Hon. Henry William Walter Horsley Beresford (1876–1924), who married Constance (née Blades) Levenston- better known as the actress Kitty Gordon and newly widowed of theatre manager Michael Levenston- in October 1904.
Hon. William Arthur de la Poer Horsley Beresford (1878–1949), who married Florence Miller, a daughter of Gardner L. Miller, in 1901. They divorced in 1919 and he married Laura Coventry, eldest daughter of Capt. St John Halford Coventry, in 1919. They divorced in 1928 and he married oil heiress Georgina Leonora (née Mosselmans) de Saurigny, only daughter of Richard Frederick Hendrick Mosselmans, in 1933. They divorced in 1940 and he married Ida Kaye in 1941.
Lord Decies died on 3 July 1893 at Bolam House, Northumberland. After his death, Lady Decies, who survived him almost fifty years until her death on 27 February 1941, lived at Heworth Hall in York.
