Family papers of the Williams family of Castell Deudraeth, 1859-1929, including a bound volume containing papers, including letters and press cuttings, relating to the general election of 1859 in Merionethshire in which David Williams stood as a Liberal against the sitting Conservative Member W. W. E. Wynne of Peniarth; scrapbooks, 1903-1929, containing press cuttings concerning the family, notably Sir Arthur Osmond Williams, and two typescript essays.

A group of documents relating to gold mining in Merioneth. It includes notes on various gold mines in the county; correspondence addressed principally to O. Parry Hughes, 1918-36; typescript evidence prepared for the Merioneth Gold Mining Inquiry, 1930, and a report of the proceedings; memoranda relating to the formation and development of the Merioneth Mining Development Committee, 1930; copies of printed reports by Professor Henry Louis on the possibilities of gold mining in Merioneth, 1930; notes on diamond drilling and its possibilities in Merionethshire; together with a few printed items, two photographs, press cuttings and miscellanea.

Transcripts of documents relating mainly to Merioneth: Instructions from the Council in the Marches to suppress felonies; charges to juries; a letter, with answer, to a gentleman in Wales touching suits in the Court of Star Chamber, 1598; a letter of recommendation of John Vaughan of Cair gay, 1601; a petition of the freeholders of Estymaner and Talpont; instructions to the Council in the Marches, 1606; a letter of Enianus, bishop of Bangor, to Lord John de Grey, 1310; orders for securing the peace of the Commonwealth; orders at Quarter Sessions, 1673; sentences against Hugh Nanney for incontinence, 1588, 1594; observations on tenures in Englefleld, Flintshire, and concerning a court held by Mr Mackworth; an order in the suit of Robert Lloyd v. Griffith Nanney, 1603; the opinion of George Lee concerning a Portuguese ship wrecked on the Merioneth coast, 1746; a draft petition for an Act to enclose Traeth Mawr and Traeth Bychan; a contract to erect a shire hall at Dolgelley, 1606; the divisions of Merioneth with their proportional assessments, 1689; a canvass for Mr Vaughan and a copy of R. W. Vaughan's address to Merioneth electors, 1796; a rental of Robert Morgan's estate; and the petition of Sir Robert Heath to Charles I.
Instructions to Sir William Bowes, Robert Bowes, and Lord Eure (Scottish border, 1589-1599), Sir George Carey in Ireland with the Earl of Essex, 1598, Mr Carrow Raleigh concerning musters, and Sir Thomas Shirley, Lord Sheffield, Dr Dale, and Mr Bodley (Low Countries, 1586-1598); instructions concerning the expedition to Spain, 1596; papers relating to the proposed Spanish marriage, 1623; speeches and petitions in Parliament, 1623-1626; a list of grants to the Duke of Buckingham and proceedings relating to his impeachment, 1626; and a letter by Ra: Eure, John Harbert, and Daniell Dunn from Breme, 1602.
Printed proclamations of the assumption of the style of King of Great Brittaine by James I, 1604, and of the calling in of testons, 2 Edward VI.
On the back of the former is a fragment of a Welsh poem beginning - 'a fi'n eiste'n obrydd...'

'Geirlyfr William Lleyn'; 'Bardhoniaeth ... William Middelton'; pedigrees and arms, mainly of North Wales families; 'cywyddau', 'awdlau', etc. by Adda Fras, Iolo Goch, Maredudd ap Rhys, Robin Ddu, Rhys Nanmor, Gwilym ab Ieuan Hen, Dafydd Gorlech, Tudur Aled, Gruffudd ab Ieuan ab Llywelyn Fychan, Wiliam Llŷn, Sion Cent, Sion Tudur, Thomas Prys, Lewis Menai, Gruffudd Phylip, Richard Cynwal, Edmwnd Prys, Wmffre Dafydd ab Ifan, Wiliam Phylip, Sion Bryncir, Siôn Phylip, Richard Phylip, Sion Dafydd Lâs [John Davies], Watcyn Clywedog, Mor[u]s Dwyfech [Morus ap Dafydd ab Ifan ab Einion], Huw Lewis, Dafydd ap Hwlcyn ap Madog, Rhisiart Brych, Dafydd Jones ('Ficer Llanfair-Dyffryn-Clwyd'), Owen Gruffydd, Sion Lleyn [John Roberts], Taliesin, Rhys Goch Eryri, Dafydd Llwyd ap Llywelyn ap Gruffudd, Sion Roger, Sypyn Cyfeiliog [Dafydd Bach ap Madog Wladaidd], Bedo Brwynllys, Mathew Owen, Edward Morus, Huw Mor[y]s, Ieuan Dew Brydydd, Huw ab Ifan, Robert Davies (Nantglyn), Robin ab Iorwerth, Rolant Huw (Graienyn), Dewi Wyn [o Eifion] [David Owen], Griffith William (Braichtalog), Goronwy Owen, John Thomas (Pentrefeidiog) [i.e. Pentrefoelas], M[organ] D[avies], Griffith Puw, Dafydd Jones ('Tailiwr'), William ab Edward ('o'r Bennar'), Thomas Edwards ['Twm o'r Nant'], Lewis Morris, Ieuan Llwyd [Brydydd], Rhys Llwyd [Pant-y-piod], Rolant [Rowland] Jones (Pandy) [Roli Penllyn], Hugh Jones (Llangwm), John Jones [Jac] (Glan y Gors) and W[illiam] Jones [Bardd Môn]; 'englynion' by several authors; material relating to persons and places in Merioneth.

Papers of W. A. Madocks, including his memoranda books, letters to John Williams (his agent at Portmadoc), 1806-1825, and some materials for his biography in the form of copies of letters from Ebenezer Thomas (`Eben Fardd'), John Thomas, Chwilog, Ellis Owen, Cefnymeusydd, and others; a 'statute book' of the 'Ancient and Renowned Borough of Tremadoc', 1805-1810, with an account of the Tremadoc Ball and Hunt; together with records from the Harbour Office, Porthmadog, including account books and registers of Portmadoc harbour, 1824-1917. Also included are records of the Festiniog and Blaenau Railway Co., 1866-1883; plans, sections and other records, 1860-1897, of the Aberystwyth and Welsh Coast Railway, the Bala and Festiniog Railway, the Beddgelert Railway, the Caernarvonshire Railway, the Caernarvonshire and Nantlle Railway, the Cambrian Railway, the Corris, Machynlleth, and River Dovey Tramroad, the Corwen and Bala Extension Railway, the Croesor Railway, the Croesor and Portmadoc Railway, the Festiniog Railway, the London and North Western Railway, the Merionethshire Railway, the Portmadoc, Beddgelert and Rhyd-ddu Railway, and the West Midland, Shrewsbury and Coast of Wales Railway; a register of shareholders and minute books of the Festiniog Refreshment House Company, 1878-1890; a minute book and share ledger of the Penrhyndeudraeth Lead Mining Company, 1875-1882; nominal and muster rolls of the Caernarvonshire Volunteers, 1860-1883, and other Caernarfonshire militia records; a minute book and papers relating to collections in Caernarfonshire towards Queen Victoria's Jubilee, 1886-1887; account books relating to slate quarries and to shipping, and miscellaneous Caernarfonshire material, 1723-[19th century].

Papers, 1634-1928, mostly deriving from and relating to the legal practice of Henry Rumsey Williams, comprising draft conveyances, abstracts of title, letters, accounts and miscellaneous papers of clients, including the estate of Wynn of Glynllifon, 1719-1840, the Griffiths family of Caernarfon and Amwlch, 1726-[1830s], Jared Jackson, 1760-1836, Plasgwyn estate, 1761-1846, Cefn Cwmwd estate, 1763-1828, Coed Helen estate, 1770-1838, Trergo estate, 1771-1832, Parry family, 1773-1788, Peniarth estate, 1773-1830, Orielton estate, 1774-1814, Bodior estate, 1778-1837, Faenol estate, 1778-1840, Arnold Robinson Burrowes, 1785-1837, Grindley family, [c. 1786]-1842, Morgan family, 1787-1839, Treiorwerth estate, 1787-1844, Evan Pritchard, 1788-1813, John Price, 1790-1844 Caerhun estate, 1791-1834, W. A. Madocks, 1799-1824, Nancall estate, 1802-1837, Morris Griffith, 1804-1832, Edward Griffith Roberts, 1805-1827, William Humphrey, 1805-1833, Plas Llanfair estate, 1805-1837, Baily Williams family, 1806-1838, Richard Garnons, 1809-1837, Cefn Hengwrt estate, 1810-1815, George Bettiss, 1810-1831, William Edwards, 1811-1836, Penrhyn estate, 1811-1837, Wyatt family, 1813-1835, Gelli Goch estate, 1815-1831, Anna Maria Wynne, 1816-1833, Robert Thomas, 1818-1839, Roberts family, 1818-1840, Bodegroes estate, 1819-1836, Hughes, Brydges and Granville, bankers, 1819-1840, Vickers family, 1820-1833, Boston estate, 1820-1839, Owen Griffith, 1822-1846, George Holmes Jackson, 1823-1841, the Rev. Hugh Hughes Wynne, 1831-1848, John Rowlands, 1832-1841, and Edward Hosier Williams, 1833, in Caernarfonshire, Anglesey, Denbighshire, and Merionethshire; legal correspondence, 1790-1848, probate records, 1727-1871, and papers relating to civil cases, 1757-1850, religion, 1788-1842, mining, 1779-1842, quarrying, 1798-1840, shipping, 1778- [c. 1841], roads and railways, 1834-1839; legal practice records, 1804-1841, and executorship papers, 1841-1855, belonging to Henry Rumsey Williams, and records of his family in Brecknockshire, Monmouthshire and Caernarfonshire, 1881-1928. Records relating to William's political activities have not survived.