Ireland is an island. On that island is the Republic of Ireland, which is often referred to as Ireland, and Northern Ireland. So you could say that the answer is Northern Ireland.
Republic of Ireland.
Great Britain is an island, therefore no country has a land border with it. If you mean the United Kingdom, then the province of Northern Ireland has a land border with the Republic of Ireland.
The Republic of Ireland shares a land border with Northern Ireland which is part of the United Kingdom.
The United Kingdom only has a land border with the Republic of Ireland.
Ireland shares a land border with Northern Ireland which is part of the UK. That makes Ireland the closest neighbour to the UK. Ireland is the offical English language name of the southern portion of the island of Ireland as used by the Government of Ireland and not Republic of Ireland or The Irish Republic.
Geographically, the British Isles are the two main islands of Britain and Ireland and all of their off-shore islands. Politically, they are divided into 'The United Kingdom of Great Britain and Northern Ireland' and 'The Republic of Ireland'. The Republic of Ireland occupies about 5/6 of the island of Ireland and 'Northern Ireland' occupies the rest. The Republic of Ireland is the only country to share a land border with the UK. No passport is required to travel between Britain and Ireland in either direction.
No British country is shared with another land. Britain is the island containing England, Scotland and Wales. You may be referring to Northern Ireland, which is on the island of Ireland, along with the Republic of Ireland. However, Northern Ireland is part of the United Kingdom, but not part of Britain. The United Kingdom's description even makes that distinction. It is the "United Kingdom of Great Britain and Northern Ireland."
yes there are no borders between northern and southern ireland
What is known as Great Britain is an island that is a neighbour of Ireland, but has no physical contact with it. What you are referring to is Northern Ireland, which is on the island of Ireland, as is the Republic of Ireland.
They are both on the same land mass, the island of Ireland. However they are two different countries.
Ireland is an island that is divided into the Republic of Ireland, which is independent, and Northern Ireland, which is part of the United Kingdom. The land itself is mostly made up of plains and low lying mountains.