Two notebooks, NLW MS 16798Ai being a printed account book for the year 1802 possibly belonging to a yeoman farmer or man of similar profession, NLW MS 16798Aii being a journal without dates and containing only rough accounts on ff. 6 verso-7.
NLW MS 16798Ai mainly contains details of accounts settled and owed together with general observations on the weather, agricultural duties, etc. There are rough accounts on inside front cover, ff. i, ii verso, 85 recto-verso, and inside back cover. The location of the writer is uncertain but may have been Monmouthshire, Gloucestershire or another county at or near the Welsh border as mention is made of travelling to Howle in Shropshire (ff. 13 verso, 42 verso, 43 verso, 44 verso), to [?Soilwell Farm] in Gloucestershire (f. 32 verso), to Hereford (f. 29 verso), and to attending Ross[-on-Wye] church (f. 23 verso).

Records of the Brogyntyn estate, home of the Ormsby-Gore family, Barons Harlech, 1296-1951. They include estate papers and deeds, legal papers, financial papers, family papers and county administration papers of the Ormsby-Gore family, their ancestors, the Maurices and the Owens of Clenennau, the Wynns of Glyn and others, such as Anwyl of Park, Clayton of Lea Hall, Godolphin of Abertanat, Lyster of Penrhos, Mostyn of Nant, and Vaughan of Corsygedol. The three main estates represented in the collection are Brogyntyn, Clenennau and Glyn, the latter constituting a major addition to the existing North Wales holdings of Sir Robert Owen upon his marriage to Margaret Wynn in 1683. The documentation also covers other, subsiduary estates acquired by marriage or inheritance, namely Llanddyn, Sylfaen, Ystumcegid, Nant, Cemais, Penrhos, Abertanat and properties in the west of Ireland. The record types include title deeds for lands in Caernarfonshire, Merionethshire, Flintshire, Denbighshire, Montgomeryshire, Shropshire, elsewhere in England and Wales, and in the Irish counties of Westmeath, Leitrim, Sligo, Mayo and Roscommon, 1296-1838; rentals, accounts and other papers associated with estate administration, [1380s]-1951; manorial records, 1429-1804; household management papers, 1662-[c. 1949]; legal and arbitration papers, 1410-1834; financial papers such as mortgages and accounts, 1492-1876; family settlements, probate records and trusts, 1485-[c. 1862]; private letters, 1582-1950; papers relating to family interests, [14th cent.]-1951; personal papers of family members, 1672-1945; royal appointments and honours, 1795-1948; central government papers, 1581-1887; county administration papers, 1518-1904; and administration records of the church, schools and charities, 1598-[1876x1904]. Other component parts of the archive are the Clenennau Letters and Papers, which combine personal correspondence with the civil and military administration of Caernarfonshire from the late sixteenth to late seventeenth centuries. Additional records, comprising Lord Harlech's Game Books (3 volumes), 1882-1933, a journal kept by W. R. Ormsby Gore of the 13th Light Dragoons, May-September 1854, two manuscript catalogues of plays, 1815, and a manuscript catalogue of the library at Porkington, 1809, were acquired in March 2017.
The Brogyntyn (Longueville) group comprises deeds and documents relating to the Brogyntyn estate, 1607-1977, deposited by Longueville Gittins solicitors who provided professional legal services to the estate.

Title deeds and other documents, 1608-1794, relating mainly to properties in Montgomeryshire and Shropshire.

Deeds and documents, 1280-1797, relating to Shropshire, Cheshire, Denbighshire, Flintshire, Montgomeryshire and Staffordshire, together with genealogical, heraldic and antiquarian notes, compiled c. 1745-c.1766 and [mid 19th cent.].

Papers, 1920-1989, of Dorothy Sylvester, including notebooks and lecture notes, 1920-1972; research papers, including notes, card indexes and press cuttings, relating mainly to her study of the historical geography of England and Wales, with special reference to the Welsh borderland; material relating to published works, 1957-1983; addresses and articles, 1928-1988; literary papers, and correspondence, 1926-1989.

Papers relating to the administration of the Plas Power estate and household, including some properties belonging to the Chirk estate, some but not all of which became part of the Plas Power estate; also included are some records from other properties in England that were owned by the Myddelton family.

An autobiography of Robert Thomas of Llanfechain, Montgomeryshire, written 1863-1864, describing his early life in Llanfechain and other places in Montgomeryshire and Salop, 1836-1852 (ff. 2-9 verso, 11-23 verso), a voyage from Liverpool to Melbourne, September-December 1852 (ff. 23 verso-51 verso, 56 recto-verso) and, in some detail, his life in the Australian goldfields between December 1852 and April 1854 (ff. 56 verso-149 verso). The volume also contains an incomplete summary of contents (f. 1 verso) and a log of his return voyage from Melbourne to London, May - August 1862 (ff. 10 recto-verso, 52-5).

Deeds, 1728-1850, relating to the manor of Golon and other properties in Radnorshire, and Ludlow, Shropshire; deeds and documents, 1778-1808, relating to the manors of Brilley and Eardisley and other properties, Herefordshire, and the manor of Aberedw and other properties in Radnorshire; and a schedule of the Whitehead estate in Radnorshire, [early 20th century].

Survey, [1600x1675], relating to Ryston, Mountgom[er]y, Wititree, Tunebert, Stocton, Woderton, Marinton, the church of Churburye, and a warren in the manor of Worthin.

A copy of W. A. Leighton: The Armorial Bearings of Shropshire Families, from a MS. of ... George Morris ... (Shrewsbury, [1885]), interleaved, with manuscript additions, corrections and additional coats of arms.