Estate and family papers of Owen and Wynne families of Peniarth, Merionethshire, [15 cent.]-[19 cent.], including groups relating to Mostyn of Nant and Mostyn and Williams of Penbedw, Flintshire, to Maurice of Lloran, Denbighshire, and to Corbet of Ynysmaengwyn, Merionethshire, including estate papers, 1630-1870, rentals and accounts; deeds, 1361/2-1963, mainly for Peniarth, Aberllefenni, Penbedw, Drenewydd and Mallwyd estates; legal papers, 1539-1848; industrial papers, 1615-1852; county administration, 1468-1874; and non-family trust papers, 1468-1878, mainly relating to the Ynysymaengwyn estate.

Deeds and documents, 1535-1920, relating to the Gwrych Castle estate of the Lloyd, Bamford and Hesketh families in Denbighshire, Flintshire, Cheshire, Lancashire and Derbyshire; minutes and other papers of the manor of Cheadle Hulme, 1735-1817; accounts of Bamford and Crimble collieries, Lancashire, 1825-1832, and of lead mining ventures in Abergele; rentals and accounts of the Gwrych Castle estate, 1818-1920; maps and plans; and pedigrees of the Lloyd family of Plas yn y Gwrych and Hesketh families.