The archive comprises entirely of deeds and documents, 1446-1934, relating to the Caerhun estate in Anglesey, Caernarfonshire, Denbighshire, and associated estates of Downing, Flintshire, and Llechwedd Garth in Montgomeryshire.

Deeds, copies of deeds and drafts of deeds concerning land and other property in the county of Denbigh (including the lordship and manor of Chirk and Chirkland and their constituent townships, etc., the lordship of Bromfield and Yale, the manor of Ysbyty Dolgynwal, the manor of Ruthin or Dyffryn Clwyd, the hundreds of Isaled and Is Dulas, and the parishes, townships, etc., of Abergele, Abenbury, Banhadla, Barrog, Bersham, Bodlith, Bodrychwyn, Borras Hwfa, Borras Riffri, Bodrual, Brymbo, Burton, Ceunant, Cilan, Cilmediw, Clocaenog, Coed Cristionydd, Cornwall, Creigiog Uwch Glan, Cristionydd Cynrig, Cristionydd Fechan, Crogen Wladys, Cynllaith, Chwibren, Chwibren Uchaf, Chwileiriog, Denbigh, Disgarth, Dutton-y-Brain, Eryrys, Esclusham, Faenol, Gartheryr, Garthgynan, Gwernosbyn, Gwersyllt, Gwytherin, Hafodgynfor, Hafodybwch, Henfachau, Henllan, Higher Chirk, Holt, Llanarmon yn Ial, Llanfair Dyffryn Clwyd, Llanfair Talhaearn, Llanfihangel, Llangadwaladr, Llangedwyn, Llangollen Fechan, Llangwm, Llanrhaiadr yng Nghinmeirch, Llanrhudd, Llansannan, Llansilin, Llanynys, Lledrod, Lleweni, Lower Chirk, Marchwiail, Melai, Minera, Moelfre, Morton Anglicorum, Morton Wallicorum, Nantyr, Peniarth, Penyclawdd, Penyfed, Rhan-hir, Rhiwlas, Rhydeidion, Ruabon, Ruthin, Sutton, Sycharth, Talhaearn, Tregeiriog, Trewern, Wrexham, Wrexham Abbott, Wrexham Regis, Y Ddwyfan and Ystrad Cynon), together with associated memoranda, articles of agreement, marriage settlements made by members of the Myddelton family, bonds of obligation made by persons resident in the county, and notes. A few of the deeds relating to Denbighshire also concern land in Montgomeryshire, Cheshire, Merionethshire, Flintshire and Shropshire.

Deeds and leases concerning land in the county of Flint (including the parishes and townships of Abenbury, Abenbury Fechan, Bangor Is-coed, Bodeithinen, Bodfari, Cilowen, Gwernafield, Hendre Bodfari and Tremeirchion), together with associated memoranda and bonds of obligation made by persons resident in the county.

Deeds and documents, relating to properties in Flintshire, mainly in St Asaph, 1365-1677.

Deeds of the Myfod family of Tremeirchion, Flintshire, 1657-1727, and of their successors by marriage, the Jones family of Ffynnon Feuno, Tremeirchion, 1746-1781, and the sale of Ffynnon Feuno to Thomas Pennant of Downing, 1784. Deeds relating to New Inn and Tanybryn, 1793-1796, Tynyrafon in Tremeirchion, 1810-1821, and properties, including Gadlys, in the parish of Holywell, 1813-1873.

Title deeds of properties acquired through purchase, lease, mortgage, marriage and inheritance by members of the Conway and Mostyn families of Nant, [mid-14 cent.], 1367-[c. 1686], mainly in the parishes of Cwm, Llanasa, Meliden and Rhiwlyfnwyd, but also in Bodfari, Gwaunysgor, Cilcain, Rhuddlan and Whitford. The earliest title deeds include a small number of fourteenth century documents involving the de Crevecoeur family, lords of Prestatyn. Further items of significance are conveyances of lands in Cwm and Diserth from 1533 to 1625 by the Lloyds of Hiraddug, who had established a marital connection to the Mostyn family. Other deeds show the acquisition of land by the Conway family, mainly in Llanasa and Meliden, between 1539 and 1624. Family settlements and associated documents of the Mostyn family, dating from 1625 to 1659, relate to lands mainly in Meliden, but also in Llanasa, Cilcain, Cwm and Whitford. Other families represented in the deeds include Holland of Prestatyn, and Prestland of Prestatyn and Wardle, Cheshire.