Family papers and estate records of the Williams family of Cwmcynfelyn, Cardiganshire, comprising rentals, 1833-[1885], valuations, [1849]-1879, financial papers, 1826-1899, deeds of the Cwmcynfelyn estate in north Cardiganshire, and in the parish of Machynlleth, Montgomeryshire 1773-1886, deeds relating to Penpompren in Llanfihangel Genau'r-glyn, 1724-1791 (including a schedule of deeds dating back to 1694), which probably found their way to Cwmcynfelyn through the marriage of Matthew Davies Williams of Cwmcynfelyn and Susanna Griffith in 1828; papers relating to the Donisthorpe and Mapperley collieries, Leicestershire, 1874-1899; papers relating to the Gogerddan estate, Cardiganshire, accumulated by George Griffiths Williams as agent until his retirement, 1852-1895; and personal papers of Mathew Davies Williams, 1821-1864.