Records acquired by the Haswell Brothers relating mainly to its clients, 1891-1956, including the North Wales Employers' Mutual Indemnity Company, 1898-1952 (the records include a notice of accidents relating to the Gresford mining disaster); United Westminster and Wrexham Collieries Ltd., 1905-1950, and the Ruabon Coal and Coke Company, 1891-1939; the Minera Silica Quarries Ltd., 1926-1940; Messrs. Charles R. Eames Ltd., 1950-1956; William Thomas and Sons Ltd., 1924-1936; Wrexham Tenants Ltd., 1928-1931; Gresford Colliery Ltd., 1920-1924; Dennis Ruabon Ltd., 1934-1945; and Brymbo Silica Quarries Ltd., 1936-1940. Also included are the administrative papers of the firm itself, mainly registers of letters received, 1906-1919, and files of press copy outgoing letters, 1914-1919.

Deeds, documents and letters, 1638-1897, relating mainly to properties in Denbighshire and Shropshire, but also Caernarfonshire, Cardiganshire, Montgomeryshire, Merionethshire, Radnorshire and Cheshire; plans relating to the activities of railway companies mainly in the parishes of Gresford and Wrexham, Denbighshire, 1845-1849; and printed material, 1863-1897.