During the Second World War the prison buildings were used as a munitions factory, before being handed back to the County Council, when it was the headquarters of the Denbighshire Library Service.

[1] The first House of Correction, or Bridewell, was built at the bottom of Clwyd Street, next to the river, in 1654, to replace the Old Court House, where able-bodied idlers and the unemployed were sent to work.

As far as is known, only one person was ever executed in the prison, William Hughes of Denbigh, aged 42, who was hanged on 17 February 1903 for the murder of his wife, his plea of insanity having failed.

[citation needed] Another colourful prison personality was John Jones, known as Coch Bach y Bala – who was a kleptomaniac and poacher who had spent more than half his 60 years in all the prisons of north Wales and many in England; he twice escaped from Ruthin Gaol, first on 30 November 1879 when he walked out of prison with three others while the staff were having supper — a £5 reward was offered for his capture, which happened the following 3 January.

On 30 September 1913 he tunnelled out of his cell and using a rope made out of his bedding he climbed over the roof of the chapel and kitchen and got over the wall; after seven days living rough on the Nantclwyd Estate several miles away, Jones was shot in the leg by one of his pursuers, 19-year-old Reginald Jones-Bateman.