Example image of eyePlorer eyePlorer map for 'Hillsborough Castle': Northern Ireland British Royal Family Elizabeth II of the United Kingdom Secretary of State for Northern Ireland Governor of Northern Ireland Monarchy of the United Kingdom Castle Hillsborough, County Down Georgian era Marquess of Downshire Government of Ireland Act 1920 Council of Ireland Lord Lieutenant of Ireland Southern Ireland Anglo-Irish Treaty Irish Free State Dublin Belfast James Hamilton, 3rd Duke of Abercorn Prime Minister of Northern Ireland Prince Philip, Duke of Edinburgh Anglo-Irish Agreement Garret FitzGerald Taoiseach Unionism in Ireland Belfast Agreement David Trimble, Baron Trimble Gerry Adams John Hume Sinn Féin Social Democratic and Labour Party Ulster Unionist Party Ian Paisley Gay Peter Mandelson Mo Mowlam Provisional Irish Republican Army Republic of Ireland United Kingdom George W. Bush President of the United States David Anderson (Northern Ireland) Hillsborough Dermot O'Neill (gardener) 105th Regiment Royal Artillery (Volunteers) Richhill, County Armagh Grace and favour U.S. – Northern Ireland Investment Conference Executive Committee of the Privy Council of Northern Ireland Official residence