Papers, 1844-1941, of the Williams family of Acre House, Acrefair, mainly comprising letters, including family correspondence and letters received from relatives in Glamorgan, from the Pugh family, and from relatives in the USA, [late 19th cent.]-[early 20th cent.]; letters to the Rev. Ebenezer John Williams, mostly relating to his duties as minister and the chapel and water works in Llanwddyn, 1882-1889; and letters to John Williams, [late 19th cent.], mostly relating to the iron industry. The archive also includes diaries of John Williams, 1844-1897; notebooks, accounts and other documents, 1856-1893, relating to the ironworks in Ruabon and South Wales; diaries and notebooks of the Rev. Ebenezer John Williams, 1869-1935 (including chapel committee notes, accounts, Sunday School registers, and sermon notes); diaries and notebooks of Rev. John Pugh, 1849-1890, (including one containing his autobiography); papers relating to Liberal Party election campaigns in Montgomeryshire and Denbighshire, [late 19th cent.]; deeds, 1842-1921, mostly relating to property in Dowlais; papers relating to schools, [late 19th cent.]-[early 20th cent.], including school notebooks, prospectuses of schools including Holt Academy, and papers relating to the founding of British schools in the Cefn Mawr district and elsewhere.

Papers of Arthur John Williams, 1881-1943, including political papers comprising letters, 1868-1911; papers relating to legal, electoral and land reforms, 1867-1911; papers relating to his parliamentary elections in Birkenhead and Glamorgan, 1880-1895; papers relating to South Glamorgan politics, 1886-1924; material concerning the National Liberal Club, 1883-1951; diaries, 1864-1911; diaries of Rose Harriette Thompson Crawshay 1868-1943; and family and financial papers, 1767-1943.

Addresses, lectures and speeches, notes and other papers, 1900-1922, relating to politics, Welsh nationalism, education, rural housing, disestablishment, army recruiting and Sir Ellis's defeat as Liberal candidate for Anglesey; press cuttings, 1883-1926; biographical material, 1949-1954, including an incomplete typescript of a biography by E. Morgan Humphreys; and political letters from Ellis-Griffith, 1873-1926, and letters to him, 1878-1925.

Letters written to T. E. Ellis, 1876-1899, from correspondents including A. H. D. Acland, D. R. Daniel, Ellis Jones Griffith, Lord Rosebery and others; drafts and copies of letters by T. E. Ellis, [c. 1879]-1899; miscellaneous correspondence and papers concerning T. E. Ellis, 1886-1929; diaries, 1889-1897; newspaper cuttings, printed matter, notes, petitions and papers on political matters, 1877-1910; and family papers, consisting mainly of letters to Mrs T. E. Ellis, 1897-1929.

Records of the Welsh Liberal Party, 1966-1988, including Executive Committee and General Council minutes, 1967-1987; Annual General Meeting papers and correspondence, 1982-1987; correspondence and papers relating to local government reform and electoral reform, transport, economic policy and nationalisation, Welsh affairs, devolution, and Welsh Liberal Party structure and finance, 1963-1987; papers relating to annual conferences, 1968-1987; papers relating to parliamentary and other elections, 1969-1989; correspondence and papers relating to individual parliamentary constituencies, 1970-1980; Local Government and Parliamentary Boundary Commission submissions, 1981-1983; Standing Committee and Policy Directorate papers, 1975-1982; press releases, 1980-1988; party publications, 1975-1981; records of county Liberal Associations, 1973-1988; and records of Caernarfon Division Liberal Association, 1961-1975.

Three additional files comprising minutes of meetings of the Welsh Liberal Party, 1981-2 and 1987. This group remains uncatalogued.