It covered the area of three former districts from the administrative county of Flintshire, which were all abolished at the same time:[1] The district was named after Rhuddlan Castle, where the Statute of Rhuddlan was issued in 1284.

[2] This was illustrated in the borough's coat of arms which showed a castle of the time of Edward I in the shield, and a Welsh dragon grasping a parchment scroll, representing the statute, as the crest.

Throughout the council's existence a majority of the seats were held by independent councillors.

[4] The council was initially based at several offices across the district, mostly inherited from its predecessor authorities.

[5] Russell House was formally opened by Prince Richard, Duke of Gloucester, on 26 November 1991.