Letters to Emily Charlotte Ormsby-Gore (née Seymour), second Lady Harlech, 1844-1876, from her husband, William Richard Ormsby-Gore, and children, 1853-1874, other relatives and friends, including Lady Clinton, [1844], Mary Jane Ormsby-Gore [c. 1869], the Duchess of Grafton, 1860, Lady Georgiana de Ros, [1860], her father, Sir George Francis Seymour, 1857-1869, her cousin, Lady Spencer, 1857-1870, and other members of the Seymour family, 1850-1876. Particular topics are: her husband 's experiences in the Crimean War, 1853-1854; charitable works, estate business and court duties in Ireland; elections in Shropshire and Roscommon, 1859; the Franco-Prussian War, 1870; Sir George F. Seymour 's involvement with the 68th regiment and recollections of the Walcheren expedition in 1809; the marriage of Laura Wilhelmina Seymour to Prince Victor Gleichen, 1860; and events in Canada during the American Civil War, 1862. The file also includes a single family letter to her daughter, Mary.

Letters to other identified recipients, predominantly members of the Fownes, Myddelton and FitzHugh families and households, and their representatives and associates, together with those of the Lloyd family after Rev. Thomas Lloyd moved to Plas Power in 1720; included are letters from William Fownes, Richard Myddelton, Mary Myddelton and Roger Mostyn; as well as a letter from [Philip, duke of] Wharton, to his sister Lady Jane Holt, 1726, expressing his concern for his family in the light of his appointment as Jacobite ambassador to the Holy Roman Empire; a letter from John Yorke with military news from 'camp between Balaklava and Sebastopol', October 1854, and a copy of his letter from 'Balaklava Harbour'; and two letters from E.J. Stracey from Balaclava, October [1854], and 'camp before Sebastopol', December 1854, concerning military affairs and the condition of the army.

Letters to unidentified recipients, mostly apparently members of the Fownes, Myddelton and FitzHugh families and households, and their representatives and associates, together with those of the Lloyd family after Rev. Thomas Lloyd moved to Plas Power in 1720; many of the letters are drafts in the hand of Mary Myddelton, and some may relate to Chirk Castle rather than Plas Power; included are a copy of a letter from an army officer north of Aberdeen, February 1715/6, to 'his ffreind att London' concerning the campaign against the Jacobites, and a letter from Captain E.W.D. Bell at Alma Heights, September 1854, concerning a recent action.