From the beautiful waters of Carling Lough right across to Derry, the Irish border stretches for 310 miles with close to a crossing for every mile
JOE.co.uk followed that border and explored the consequences of a no deal Brexit for the two countries and the people between them.
The journey takes in Sniper Country in Crossmaglen, Northern Ireland, where the IRA shot dead a significant number of British soldiers just short of the border. As well as a business cut in half by the border and the fireworks huts that pepper the rest of it. Their wares are illegal in the Republic and so do a roaring international trade.
Concerns about a return to the violence seen in Crossmaglen are totally valid.
When the UK leaves the EU the two will suddenly share a major land border. If the UK leaves without a deal these 310 miles then become a security risk.
How can you control the flow of people or illicit goods without border infrastructure?
Conservative estimates place daily commuters across the Irish border at 35,000 people. They travel on roads like the one from Clones to Cavan.
Concession Road crosses the border four times in the space of six miles. Often the only indication you’ve crossed an international boundary is a change in road signs and markings.
Will commuters between Clones and Cavan be forced to stop at four different customs check points in a post-no deal world?
Indeed, if a hard border went up, an Irish enclave would be created by the river there, which does not have a bridge across it.
So the people living in this area of the Republic of Ireland would have to cross through Northern Ireland to access the rest of their country.
Outside the city of Derry, the border follows a river but veers off so that the strategic port is included within Northern Ireland.
But a strong community of republicans exists in Derry.
Since the gerrymandering of the border, which splits away from the Foyle right where I’m stood now, areas of the city are so hostile toward the police that they are forced to travel in armoured convoys, or else be confronted with petrol bombs and bullets.
Most paramilitary groups here put down their weapons more than 20 years ago.
But the prospect of a no deal Brexit, and resulting hard border, across the island of Ireland threatens that hard-won and fragile peace.
