Swyddfa'r Syr formerly held various county departments including the county archives. The old police station was housed in one area. It was the location of the police station in the S4C series Y gwyll (Hinterland).
Originally built as the Queen's Hotel, the building was designed by architects Hayward and Davis in a 'Hôtel de Ville' style and built by George Lumley of Aberystwyth for the Hafod Hotel Company, or Mid Wales Hotel Company. It was opened in 1866. The plans were signed by Davis, and the hotel is contemporary with, though more stolid than, Hayward's Duke of Cornwall hotel in Plymouth, but lacks the virtuoso roofscape of the Plymouth building. The Cambrian News published visitor lists during the summer months. The 83-bedroom hotel had special ground-floor provision for the infirm. Quartz and ore panels are retained beneath the ground-floor windows, and there is extravagant stained-glass on the mezzanine. Vestiges of former splendour remain in the Archives search room, with its acanthus plasterwork, mantlepiece and mirror, and in the former New Assembly rooms - now the 'Cambrian Hall' - with 'Q H' on the iron spandrels. Post-1945, the hotel was converted by G. R. Bruce, County Architect, into the County Offices.