Estate and family records of the Chirk Castle estate, mainly in Denbighshire, comprising deeds from 1284; manorial records, mainly of the lordship of Chirk and Chirkland, 1322-1853, including receiver's accounts, ministers' accounts, court rolls, etc.; records of the estate's involvement in the coal, iron and lead industries in Denbighshire from 17 cent.; Denbighshire Quarter Sessions records, including order books, 1647-1675, rolls, 1643-1699, and a book of indictments, 1670-1690; Denbighshire militia records, 1602-1797, and related local government records, 1602-1811; business papers of Sir Thomas Myddelton (1550-1631); personal and estate correspondence from c.1600; literary manuscripts, c.1630-1887; and parliamentary election papers for Denbighshire and Denbigh boroughs, 1681-1852, including papers relating to quo warranto proceedings against the mayor and burgeses of Holt, 1739-1743.
Ten designs for stained glass panels, with armorial pedigree of the Myddelton family attributed to A. W. N. Pugin and John Hardman Powell; three hundred and thirty-two volumes relating to the Chirk Castle estates; a collection of miscellaneous volumes and documents relating to the Chirk Castle estates, including an account book of the Nangwrud Slate Quarry, rentals books, account books, volumes relating to the Black Park Colliery, a rabbit account book, and other papers; and an indenture, 1812, relating to Bodlith, Llansilin, part of the Chirk Castle estate were acquired. These remain uncatalogued.
A manuscript account book for Sir Richard Myddelton's properties at Chirk Castle and Soho Square, London, 1686-1700 and 1748-1752.
A manuscript Steward's letter-book relating to Chirk Castle, 183501838.

The file comprises letters by Robert Griffith, 1801-1815, to his father, mother, grandmother and brother, Edward, on schooldays at Oswestry, the headmaster, Mr Donne, as mayor of Oswestry, activities of volunteer troops, including his father's march to Caernarfon as Major in the Denbighshire Volunteers, illness of Mrs S. Price, 1804, death of [Owen] Ormsby of Porkington, 1804, and an intended marriage between his daughter and Lord Kirkwall, Oswestry races, shooting, Nelson's victory, 1805, visits to Bangor, Donnington and Bath, Lord Bulkeley's birthday celebrations, 1807, university life at Oxford, misbehaviour of Charles Wynne, effects of recent wars in Europe, 1815.

The series comprises letters to John Wynne Griffith of Garn, 1784-1833, many of them from creditors, lawyers and the family of Robert Watkin Wynne concerning legal and financial problems of the Plasnewydd estate trust, 1805-1822. Other, numerous correspondents include: [Sir] John Bayley, 1830, Robert and Charlotte Myddelton Biddulph, 1802-1811, 1820, William Cleaver, Bishop of Bangor, 1806, John Heaton, 1809-1822, Dr David Hughes of Jesus College, Oxford, 1806-1815, Lord Kirkwall, 1805-1813, John Moore, Archbishop of Canterbury, 1791, Robert Myddleton, 1815, Lord Orkney, 1810, on the following recurrent topics: business of the Denbigh burgesses; commons and enclosures; the Western Denbighshire Local Militia, especially the court martial of Captain John Davies in 1813, and non-payment of the Denbigh Foresters Yeoman Cavalry; presentation of an inscribed silver vase to Sir Watkin Williams Wynn, 1815-1816; military career of Thomas Griffith in India and the East Indies, and recovery of Java prize money after his death; careers of J.W.G.'s other sons; Denbigh borough and parliamentary elections; estate business and land conveyances; the contemporary political and social scene. Further correspondents are: Charlotte and Beriah Botfield, 1819-1822, on natural history, high society gossip and schooldays at Harrow; Lord Dinorben, 1832-1833, arranging a civic dinner and ceremony to enter the Duke of Sussex's name in the Denbigh Corporation books; John Lloyd of Glyn Nannau, 1808-1815, regarding the Garthmeilio estate; William Davies Shipley, Dean of St Asaph, 1803-1820, concerning application of the Poor Law in St Asaph and Rhuddlan, rights of common and enclosures on Rhuddlan Marsh, death of Conway Shipley; S. Thompson, 1822, reporting on Mrs Botfield's health; John Wilkin, 1822-1828, on crown rents; John Copner Williams, regarding elections and alterations to the jurisdiction of the Court of Great Sessions, 1806-1829; Sir Watkin and Charles Williams Wynn, 1815-1833, mainly on property tax and shooting rights. -- The series also contains several letters of significant botanical and horticultural importance from [Heneage Finch], Earl of Aylesford, 1799, [Sir] Joseph Banks, 1794, William Bingley, 1798, Hugh Davies, 1801, James Dickson, 1796, John Fenton, 1830, Edward Hasell, 1794, James Hunter, 1797-1820, Jonathan Stokes, 1788, Robert Teesdale, 1798, Dawson Turner, 1802-c. 1824, James Watt, 1807, and William Withering, senior and junior, 1796-1821.

The group comprises general records relating to the organisation of local militia groups, particularly in Denbighshire, 1801-1813, 1871-1876, and papers deriving from the involvement of John Wynne Griffith in a court martial in the Western Regiment of Denbighshire Local Militia, 1813.

A group of submissions from the War Office to Queen Victoria relating to the Royal Anglesey Militia, 1867; the Denbighshire Regiment of Yeomanry Cavalry, 1876; the militia regiments of Denbighshire and Merioneth, 1876; the militia regiments of Radnorshire and Brecknockshire, 1876; the Royal Carnarvon Regiment of Militia, 1876; the Royal Cardigan (Rifle) Militia, 1877; the Royal Anglesey (Light Infantry) Militia and the Royal Anglesey Engineers Militia, 1877; etc. All the submissions carry notes of approval in the hand of theQueen. Also included in the group are a schedule of establishments of Welsh militia regiments [c. 1867], and an explanatory memorandum, 1867, by J[onathan] Peel, secretary at war, touching the wish of the lords lieutenant of the Welsh counties to return to the old system of independent corps.