Development Board for Rural Wales records, containing minutes and other papers of the Board and various committees, 1977-1994; general administrative files concerning the establishment of the Board, its functions and responsibilities, and correspondence with other organizations, 1966-1990; construction files containing correspondence, contracts and estate plans relating to housing and industrial developments executed by the Board, particularly in Newtown, 1968-1993; records such as correspondence, minutes, notes and other papers relating to research studies on economic and social life in Mid-Wales carried out by the Board, 1968-1995; files relating to the Board's marketing and promotional strategy, 1978-1991; and press releases, 1977-1990; Mid-Wales Development Corporation records, 1962-1979, including annual reports, 1969-1977, minutes and papers of the Board and various committees, 1968-1979, and seal registers relating to MWDC projects, 1968-1976, containing compulsory purchase orders, contracts, leases and other documents.

An additional three files relating to the Development Board for Rural Wales, being DB/CF/101/1; DB/CF/101/2; DB/CF/101/3 – (Extension to Goodall & Swanwick factories at Dolgellau; factories at Dolgellau; and extension to Marian Park Industrial Estate, Dolgellau). These remain uncatalogued, and are closed for ten years from the date of the latest document in each file.

Records relating to David Owen & Son, 1860-1958,including account books, 1860-1958, time sheets, 1945-1958, letter books, 1921-1943, and business papers and correspondence, 1916-1957.

Deeds and documents relating to properties mainly in Montgomeryshire, 1615-1910.