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.