Rhuddlan in the county of Denbighshire (Welsh: Sir Ddinbych) is in the north-east of Wales (Cymru). Rhuddlan has the highest concentration of Mesolithic sites in Wales. The Mesolithic period of pre-history, sometimes called the middle stone age is dated between 9,600 and 4,000 BC. An archaeological dig, carried out in October 2020, at a site designated for development on Castle Hill, Rhuddlan, has uncovered a 9,000 year old site with more than 300 stone age tools and artefacts.