Plaid Cymru was founded in Pwllheli’s Maes Gwyn building on 5 August, 1925 - a century later, the party will return to mark the milestone.

That year the National Eisteddfod was in Pwllheli. During it, six men came united two movements – Byddin Ymreolwyr Cymru (the Home Rule Army of Wales) and y Mudiad Cymreig (The Welsh Movement) – to establish what would become the National Party of Wales. The party became Plaid Cymru in 1945.

Three of those – Saunders Lewis, David John Williams and Lewis Valentine – were imprisoned in 1936 for setting fire to Penyberth RAF base in protest against the militarisation of Wales.

Now, in June 2025, a special festival will take over the Maes to honour the party’s formation, coordinated by former MP Hywel Williams.

Everyone is invited to the festivities on the Maes on 21 June, whether they are Plaid Cymru members or not. The day will feature music, speeches, stalls, and children’s activities, with celebrations continuing into the evening with a folk gig at the Penlan pub featuring Gwilym Bowen Rhys, Geraint Lovgreen, and a band of accordionists.

The event starts at 1.30pm with stalls, entertainment and family activities, followed by formal speeches at 2pm by Liz Saville Roberts MP, Dafydd Wigley, Kirsty Blackman MP , Mabon ap Gwynfor MS, and Rhun ap Iorwerth MS. Performances by Gwenan Gibbard, Meinir Gwilym, Pys Melyn, Gwyneth Glyn, Twm Morys, and more will take place.

Hywel Williams said: “I’m extremely proud the party is holding the first major event of its centenary celebrations here in Pwllheli – the very place where it all began.

“This will be a joyful and uplifting event – a time to celebrate and give thanks for the dedication of Plaid Cymru members over the past hundred years, and to look ahead to the opportunities before us, particularly the Senedd elections in 2026.”