Ireland

Ireland is an island located due west of most parts of Great Britain. The majority is part of the the Republic of Ireland, while most of the Ulster province is a seperate country of Northern Ireland and part of the United Kingdom.

Humans sometimes mistakenly assumed Gallifrey was a place in Ireland. (DW: The Hand of Fear, Human Nature).

In 1649, The Doctor, Ace and Hex visited Ireland during Oliver Cromwell's siege of Drogheda. (BFA: The Settling)

In the 29th century, Northern Ireland was still part of the United Kingdom. (DW: The Beast Below)

Ireland was the home of Sean (DW: The Underwater Menace), Sean Flannigan (DW: The Wheel in Space), McDermott (DW: Terror of the Autons), Casey (DW: The Talons of Weng-Chiang) and possibly Luke Rattigan (DW: The Sontaran Stratagem/The Poison Sky).

Chip (DW: New Earth) and Thomas Kincade Brannigan (DW: Gridlock) both had Irish accents, but neither character likely had ever been to Ireland on Earth. Their accents suggested that Irish culture survived in some form on New Earth.