The National Eisteddfod of Wales has run every year since 1861, with three gaps: 1914 for the outbreak of the First World War, and 2020 and 2021 for the COVID-19 pandemic. It alternates between north Wales and south Wales each year, hosted by a different region. Since 1950 it has been conducted entirely in Welsh: every competition, every adjudication, every announcement on the stages of the Pavilion and the side fields. About 6,000 competitors enter, which gives the festival a claim - alongside larger pop and rock festivals - to be one of Europe's largest music and poetry events. It is the longest continuous public competition for Welsh-language culture, and the most important annual landmark in the calendar of Welsh literary and musical life.

It was the seventh time the National Eisteddfod had been held in Wrexham, and the ninth in the wider county borough. The 2011 Wrexham Eisteddfod had lost between £80,000 and £90,000, making the council cautious about hosting again so soon. The momentum to return came as part of Wrexham's bid for UK City of Culture 2029 - the council had been one of four finalists for 2025, losing to Bradford, and the National Eisteddfod was one of seven major events used to strengthen the second bid. Rumours emerged in July 2022; Wrexham County Borough Council committed £300,000 in June 2023; the National Eisteddfod confirmed Wrexham on 1 August 2023. The Isycoed location - on the eastern edge of the city, near Wrexham Industrial Estate - was finally announced on 24 October 2024, after months of delay.

Every National Eisteddfod has a Chair, an elaborate piece of furniture awarded to the year's winning poet of an awdl - a long poem in strict-metre Welsh cynghanedd. The 2025 Chair was designed by Gafyn Owen and Sean Nelson, and built entirely around symbols of Wrexham. The arches of the chair's back echoed the arches of Pontcysyllte Aqueduct. The seat was red - the colour of Wrexham Association Football Club, the team co-owned since 2020 by actors Ryan Reynolds and Rob McElhenney. The crest at the top referenced the Racecourse Ground, the club's stadium and the oldest international football ground still in regular use. The chair was won by retired university professor Tudur Hallam, who had won before but had been spurred to enter again after a diagnosis of untreatable cancer. His winning poem described receiving the diagnosis at Glangwili Hospital. Fifteen poets had entered - the highest number since 1989.

On Sunday 3 August, the folk singer and former Plaid Cymru politician Dafydd Iwan performed on the main stage for the final time. He had appeared at every National Eisteddfod since 1965 - sixty consecutive years - making him the festival's longest-serving regular performer. His songs, including 'Yma o Hyd' ('We're Still Here'), had become unofficial anthems of the Welsh national football team during their qualifying campaigns and Euro 2020 run. The crowd at Isycoed for his farewell set knew this would be the last time. They sang it back to him. Gold medals went to the painter Gareth Griffith, who had been exhibiting at the Eisteddfod since the 1970s, for fine art; and to London-based architecture practice Manalo & White for their conversion of St Mary's Church in Bangor into an arts and performance space.

On 27 April 2024, the Gorsedd Cymru - the assembly of bards, druids and ovates - held the proclamation ceremony in Wrexham, processing from Coleg Cambria Yale through the city to Llwyn Isaf in front of the Guildhall. The ceremony publishes each year's list of competitions. New Gorsedd members were inducted in green and blue robes - among the 2025 inductees were the politician Rhun ap Iorwerth, the broadcaster Dewi Llwyd, and figures from as far afield as Washington D.C. and Patagonia (Clare Vaughan of the Welsh-speaking community in the Chubut valley). Wrexham University ran a 10-week course called 'Croesawu'r Eisteddfod' - 'Welcoming the Eisteddfod' - to prepare locals for the festival. They also built a virtual version of the Maes in Minecraft. The Welsh Government provided a £200,000 grant to help locals on lower incomes attend. By the time the gates closed on 9 August, the festival had attracted estimated economic benefits of several million pounds to the region - a story Wrexham's City of Culture bid will be telling at length.