Following Britain's decision to leave the European Union, many of Ireland's 6.4 million people are struggling to absorb the shockwaves from across the sea.
"We are worried about a hard border being reintroduced and the [Northern Ireland] peace process," says Paddy Malone, a spokesman for the Chamber of Commerce in the Republic of Ireland border town of Dundalk, which lies halfway between Dublin and Belfast.
"At least 3 billion euros has been spent on peace projects in Northern Ireland since 1995, and half of that came from the EU," he says.
"Every day there are thousands of people passing through Dundalk, going in either direction on the way to work," Malone says. "They need to be able to predict how long their journey will take so they can pick up children from creches and so on.
"Everything will change if there are checkpoints on a regular basis or, even worse, on an irregular basis."
The Brexit vote has thrown up the problem that the 4.6 million people in the Republic of Ireland will remain in the European Union while the 1.8 million people in Northern Ireland - still under British jurisdiction - will be shut out, despite 56 per cent of voters there opting to stay in the EU in the June 23 referendum.
Dundalk, Malone fears, could not withstand a repeat of the shopping exodus of eight years ago when southerners flooded across the border to shop in the nearest Northern Irish town, Newry, as the euro soared against sterling.
"Dundalk is the poorest town in the border region. It is deprived because of the Troubles and because of being close to the border," he says.
"The Troubles" is the term the Irish use for the sectarian violence in Northern Ireland that lasted from the late 1960s to the Good Friday peace deal in 1998.
"In the last few years, the area was beginning to recover. Last Christmas was the first time that retailers in the town told me that they had a good Christmas since 2007-08," Malone said.
But it is not all gloom for Dundalk.
"We have attracted investment from PayPal and eBay, and 10 per cent of the workers are Polish," Malone says. "There are more people travelling from the North to work here than are going the other direction.
"It is a great place to relocate and we are hoping that some companies leaving the UK will come to Dundalk, which is just 40 minutes from Dublin airport."
The biggest short-term fears are for the town are retail, currency and transport.
"We expect retail will be hit badly," Malone adds.
Farming is already being hit in the border region with fluctuations in sterling affecting beef prices, according to Tony Fitzpatrick, a beef farmer from County Cavan. Fitzpatrick's farm is located 10 kilometres south of the border.
"There is concern at a drop in cattle prices in the mart this week as a result of the fluctuation in sterling. Northern buyers are not buying," he says.
Tourism is another area that may be jeopardized as a result of the Brexit. Britain accounts for 50 per cent of tourists to Ireland, with tourism from the United States also very important.
"We had just managed to start promoting the Carlingford Lough area. How can I sell this area to an American tourist if I tell him he needs to get two types of visas depending on which side of the Lough he is on?" Malone says.
It is not just people in the border region who fear the effects of Brexit.
Charles Buckley lives in Ireland's south-west and runs a business, eApplications Consulting Limited.
"Brexit undermines confidence in the early days of a tangible recovery in Ireland," Buckley says. "The economic uncertainty, combined with the currency issue, negatively impacts the prospects of doing business in the UK.
"I am concerned about political stability in Ireland, Northern Ireland, the UK, and especially in Europe." he says.
"On a personal level as a self-employed person, I worry about the consequences for market rates for services in the United Kingdom and for pension values."