Ireland

King Anguish of Ireland appears in some versions, often as an early opponent or ally of Arthur. Iseult, central to the Tristan and Isolde story, is sometimes presented as his daughter. Some Arthurian accounts depict Arthur conquering Ireland as part of his empire-building, though this contradicts other narratives.

Places like Tir na nÓg or Mag Mell, Irish depictions of the Otherworld, are sometimes linked to Avalon, Arthur's final resting place. Glastonbury Tor in England supposedly hides Arthur's grave, but some versions claim he returned to Avalon, often identified with Irish islands like Inis Avalon or Lough Derg.

While King Arthur is primarily linked to Wales and England in the Arthurian legends, there are a few interesting places in Ireland associated with him through folklore and later literary additions. According to some Welsh traditions, Arthur fought battles in Ireland, including one against Fionn mac Cumhaill, a legendary Irish hero. The Hill of Tara, a seat of ancient Irish kings, is sometimes mentioned as a location of these battles.

Slieve Fuad, located in County Wicklow, this mountain peak is associated with the legend of Diarmuid and Gráinne, an Irish love story with parallels to Tristan and Iseult, which itself is linked to the Arthurian cycle. Some believe Slieve Fuad could be the mountain where Diarmuid was fatally wounded by a boar, similar to how Arthur was wounded in some versions of the legends.

The ancient tomb passage mound of Knocknarea in County Sligo is sometimes linked to Queen Maeve of Connacht, a powerful warrior queen who appears in some Arthurian tales. While there's no direct connection to Arthur himself, the association with a strong female figure from Irish mythology adds another layer to the legend.

The monastic site of Glendalough in County Wicklow features St. Kevin's Church, where a stone slab known as "Arthur's Stone" can be found. The slab itself has no proven connection to the legendary king, but the name adds to the local folklore and highlights the intertwining of Celtic traditions.

Lough Gur (County Limerick) is an ancient lake and archaeological site containing numerous megalithic monuments, some of which are associated with Arthurian figures. Legend claims that Arthur's knight, Diarmuid Ua Duibhne, hid out here after being pursued by the jealous king Fionn mac Cumhaill.

Knocknaneen in County Tipperary is a hilltop fort said to be the burial place of Finn mac Cumhaill, Arthur's legendary Irish counterpart and rival. Some believe that Arthur and Finn fought a final battle here, with Finn being mortally wounded.

Glenveagh Castle (County Donegal) is a 19th-century castle built on the site of an older fortress supposedly owned by King Arthur's sister, Deirdre of the Sorrows. Local folklore tells of a hidden tunnel leading from the castle to Lough Veagh, where Arthur's treasures are said to be buried.

Slieve Gullion in County Armagh is a mountain range home to numerous ancient monuments and megalithic tombs. One legend claims that Arthur and his knights used to hunt here, and another associates the mountain with the mystical realm of Annwn, the Celtic otherworld.

It's important to note that these connections are mainly based on later literary additions or local folklore, not core parts of the Arthurian legends. However, they offer an interesting perspective on how the Arthurian mythos has been adapted and integrated into Irish culture, showcasing the shared Celtic heritage between Ireland and Britain.

Ultimately, the Ireland-Arthur connection is a captivating web of possibilities, inviting you to explore the rich tapestry of Celtic mythology and legend.