Papers, 1743-1994, of or relating to Margaret Mostyn Jones of Wern House, Mostyn, Flintshire, and to members of her family, and including a journal, 1861-1864, kept by her while employed by Augusta Hall, Lady Llanover; correspondence, 1876-1932, to and from Margaret Mostyn Jones, including letters, 1890-1894, written to members of her family while living in Ohio; an autobiographical essay, 1929-1932, by Margaret Mostyn Jones; together with papers, 1743-1874, mainly of Flintshire interest.

Extracts of Flintshire interest from NLW MSS 1557 and 1593, from printed sources and from parish registers and other records of Dyserth, Gwaunysgor, Llansannan, Meliden, etc.

Deeds and documents (1668-1882) relating to properties mainly in in co. Flint (Axton, Bistre, Caergwrle, Coleshill, Cwm, Cwm Uwchglan, Diserth, Estyn or Hope, Hawarden, Holywell, Hope, Hope Owen, Huriathicke, Kilken, Kinnerton, Mould, Newmarket, Northop, St Asaph, Shordley, Skeiviog, and Whitford), but also in cos Denbigh (Denbigh, Henllan, Llanrwst and Lleweny), Chester (Chester and Dodleston), Brecknock (Devynnock), Anglesey (Amlwch, Coedana, Llanerchymedd, Llanbadrug, Llanddyfnan, Llanfechell and Llanfihangel Tre'r Beurdd), Montgomery (Berth Lloyd) and Pembroke (Amroth). The main families were Mostyn of Mostyn Hall and Hope of Broughton and Hope.

'Notes on Places and Objects in Flintshire and Denbighshire' [and Caernarvonshire], including the parishes and churches of Bodelwyddan, Bodfari, Caerwys, Cilcain, Cwm, Dyserth, Flint, Gwaunysgor, Halkin, Hawarden, Broughton (St Mary's Church), Hawarden (St John the Baptist, Pentrobin), Holywell, Hope, Llanasa, Llanfynydd, Meliden, Mold, Nannerch, Nerquis, Newmarket, Northop, Rhuddlan, Rhyl, St Asaph (parish church and cathedral), Tremeirchion, Treuddyn, Whitford, Ysceifiog, Bangor-is-y-coed, Bettisfield, Hanmer, Is-y-coed, Marchwiel, Overton, Worthenbury, Abenbury Fawr, Allington, Abergele, Bersham, Bettws yn Rhos, Brymbo, Bryneglwys, Bylchau, Burton, Cefn (St Asaph), Cerrig-y-drudion, Chirk, Clocaenog, Denbigh, Derwen, Efenechtyd, Eglwysfach, Erbistock, Esclusham, Gresford, Gwytherin, Henllan, Holt, Llanarmon yn Iâl, Llanarmon Mynydd Mawr, Llanbedr Dyffryn Clwyd, Llanddoget, Llandegla, Llandrillo yn Rhos, Llandyrnog, Llanelian yn Rhos, Llanfair Dyffryn Clwyd, Llanelidan, Llanfair Talhaiarn, Llanferres, Llanfihangel Glyn Myfyr, Llanfwrog, Llangadwaladr, Llangedwyn, Llangernyw, Llangollen, Llangwm, Llangwyfan, Llangynhafal, Llannefydd, Llanrhaiadr yn Cinmerch, Llanrhaiadr ym Mochnant, Llanrhudd, Llanrwst and Capel Garmon, Llansannan, Llansantffraid Glyn Ceiriog, Llansantffraid Glan Conwy, Llansilin, Llantysilio yn Iâl, Llanychan, Llanynys, Marchwiel, Minera, Nantglyn, Pentrefoelas, Ruabon, Ruthin, St George's, Stansty, Trebrys, Trefnant, Wrexham, Ysbyty Ifan, Conway, Llangystennin, Llanrhos (Llandudno) and Llysfaen. Many illustrations of churches, houses, etc. have been included and there are additional notes by Susan Mainwaring (of Henblas, St Asaph).

Pedigrees, coats of arms and, in some instances, bookplates, etc. of various families, including those of Ford-Hughes, Hughes of Abercery, Lloyd of Peterwell, H. Crampton Lloyd, Mackworth of Neath, Sir Thomas Macdonald Miller, 4th bart, Phillipps of Picton Castle, Meyrick of Pembrokeshire, Meredith of Pentrebychan, Mason of Montgomery and Salop, Crompton-Roberts of Monmouthshire, Newborough of Caernarvonshire, Williams-Bulkeley of Baron Hill, Davies Cooke of Gwysaney, Cunliffe of Acton, Powys barons Tilford, Talbot of Dinevor and Rice of Newton, Thomas of Wenvoe, Saunders of Largay, and Lloyd of Bronwydd; a copy, printed in 1753, of an Act of Parliament relating to the navigation of the river Dee; a copy of an article by Henry Taylor (1845-1927) of Chester and Flint entitled 'Early lead miners brought from the High Peak to work in Flintshire'; miscellaneous letters, including one written in 1868 by Connop Thirlwall (1797-1875), bishop of St Davids.

Papers connected mainly with the activities of David Pennant of Downing, Flintshire, son of Thomas Pennant. They include material relating to affairs in Flintshire and north-east Wales in general and the Holywell district in particular and consist of letters from Henry Chambers, Edward Jones (David Pennants secretary or agent), F. R. Price (Bryn-y-pys), C. Oldfield (Perthyterfyn), Henry Parry (vicar of Llanasa), J. Oldfield, David Edisbury, D. Scott, etc.; drafts and memoranda by David Pennant; papers relating to The Charity for the Relief of the Poor Widows and Orphans of Clergymen who officiated in the diocese of St. Asaph, Flintshire and Denbighshire parliamentary elections and political affairs, parliamentary reform, poor-law relief, soup kitchens, canals, collieries and colliery strikes, public celebrations, the Holywell Loyal Volunteers, church schools, clothing clubs, eisteddfodau, auction sales, the Flintshire Dispensary, the Holywell Annual Vestry, the Holywell Hunt, etc.; a Latin poem; etc.

Rentals of crown and other lands and manors in various parts of North Wales, including rents due to John Edwards, Chirk, together with three documents relating to land in the lordship of Chirk and Flintshire.

Deeds purchased from W. A. Evans, relating to Denbighshire, Flintshire and Anglesey, 1310-1795.

Papurau ymchwil yn ymwneud â'i draethawd MTh 'Bywyd a Gwaith William Williams o'r Wern 1781-1840' (Bangor, 1981) a'i draethawd MPhil 'Astudiaeth hanesyddol o Annibynwyr Siroedd Dinbych a Fflint 1863-1953 (Bangor, 1993),[1981]-1993 = Research papers relating to his MTh thesis 'Bywyd a Gwaith William Williams o'r Wern 1781-1840' (Bangor, 1981) and his MPhil thesis 'Astudiaeth Hanesyddol o Annibynwyr Siroedd Dinbych a Fflint 1863-1953' (Bangor, 1993), [1981]-1993.

Papurau Robert Roberts,1934-1954, gan gynnwys llythyrau, nodiadau, llyfrau lloffion a defnyddiau pellach yn ymwneud â'i waith ar hanes a llenyddiaeth Gogledd Cymru, ac ar Absalom Fardd. = Papers of Robert Roberts, 1934-1954, comprising letters, notes, scrapbooks and other material relating to his work on the history and literature of North Wales, and to Absalom Fardd.