Ireland

 was an island on Earth. It was home to two states: Ireland, informally known as the Republic of Ireland, and Northern Ireland, which was a part of the United Kingdom until at least the 33rd century. (TV: The Beast Below)

Many humans mistakenly assumed Gallifrey was a place in Ireland. (TV: The Hand of Fear, The Invisible Enemy, Human Nature; PROSE: Dream a Little Dream for Me, AUDIO: Fugitives, The Warren Legacy; COMIC: Gaze of the Medusa) Andrew Harper made a similar assumption about Traken. (AUDIO: Autumn)

Early history
During the late 10th and early 11th centuries, Ireland was the site of a major power struggle between the Norse King Sitric Silkbeard of Dublin and the Irish-born King Brian Boru of Munster. Following the first Leinster Revolt in 1000, Sitric's power was severely diminshed. In 1006, he lamented that he had become little more than a lapdog to Brian.

The Book of Kells was crucial to this power struggle. It was a powerful symbol of Irishness. Sitric was concerned that if Brian gained possession of the book, he would be able to use it to gain control of Dublin and Ireland as a whole. In 1006, he sent one of his warriors, Olaf Eriksson, to enlist the Abbey of Kells' chief librarian Brother Bernard's assistance in protecting the book so as to prevent Brian from using it as a pawn to place himself on the throne of Dublin.

Although Sitric's plan to keep the book out of Brian's hands was successful, his position was further destabilised by a second revolt in Leinster several years later and the Battle of Clontarf in 1014. The Eighth Doctor warned Brother Bernard to stay away from Clontarf during that year. (AUDIO: The Book of Kells)

At some point, the First Doctor visited Ireland. (PROSE: The Sorcerer's Apprentice)

In the 14th century, the Second Doctor, Jamie McCrimmon and Victoria Waterfield visited Ireland. (PROSE: Screamager)

In 1399, King Richard II of England visited Ireland. (AUDIO: The Doctor's Tale)

In September 1649, the Seventh Doctor, Ace and Hex visited the Kingdom of Ireland during Oliver Cromwell's siege of Drogheda and Wexford. Hex's grandmother Hilda Schofield had previously told him about these incidents, which he described as being among the worst atrocities in Irish history. (AUDIO: The Settling)

Following the Glorious Revolution in November 1688, there were many deaths in Ireland. Jamie attempted to use this to justify altering history in an argument with the Second Doctor. (AUDIO: The Glorious Revolution)

In 1769, the future Duke of Wellington was born in Dublin to an influential, if hard-up, aristocratic Anglo-Irish family. His name was Wesley – the Honourable Arthur Wesley, to be precise. Later the family name reverted to its original form, Wellesley. (PROSE: World Game)

19th century
Branwell Damien Fleming was born in Ireland in 1878 and died there in 1935. (AUDIO: Iterations of I)

In 1879, Victoria was Queen of the "United Kingdom of Great Britain and Ireland." (TV: Tooth and Claw)

The Eighth Doctor's companion Molly O'Sullivan was born in Ireland in 1891. (AUDIO: The Great War, X and the Daleks)

20th century
Sinead Iona Fleming was born in Ireland in 1905. She was murdered by her husband Branwell Damien Fleming on Fleming's Island off the coast of the country in 1930. (AUDIO: Iterations of I)

Monaghan, located in Ireland, was the birthplace of Michael Gibney. (PROSE: The Lost Skin)

In December 1981, the Fifth Doctor, Adric, Nyssa and Tegan Jovanka encountered the I and the I Predator on Fleming's Island. (AUDIO: Iterations of I)

21st century
Shortly after Miracle Day in 2011, Ireland went bankrupt, as did Greece. (TV: End of the Road)

Irish soldiers were a large part of the United Nations Third Tactical Brigade, the first forces sent to Mars in the Thousand Day War in 2086. (PROSE: Transit)

Other references
Tecteun hid some of the truth about the Timeless Child in the Matrix in the form of events that happened in Ireland. (TV: Ascension of the Cybermen/The Timeless Children)