Around 15,000 people are crossing the border every day for work or to access education alone, research has shown.
The figure was among data revealed at a conference staged by Derry-Strabane and Donegal Councils charting efforts being taken to develop the entire region and preparations for the challenges expected by Brexit.
Loretta Mc Nicholas, Research and Policy Manager with Donegal County Council, who is helping lead a scoping exercise ahead of Brexit, said the most recent cross-border flow studies show that a high concentration of Donegal residents working in Derry live in the region from Inishowen down to Lifford.
“In total 14,800 people cross the border each day for work and study purposes, of which 6,500 come from Northern Ireland into the Republic, and 8,300 from the Republic into Northern Ireland. Of Donegal’s workforce approximately 7.6% of it are cross-border workers,” she said.
“But we know that people cross the border for a number of other reason. They cross the border to access health care.
“In terms of accessing educational services, at any one time there are approximately 40,000 students studying in our north west area, in the Letterkenny Institute of Technology and the North West Regional College, and the University of Ulster.
“So, the imposition of any type of a border would have implications for the free movement of people and it raises a number of key questions- would the common trade area remain? Would checkpoints be in place? Would mobility be modified? Would travel visas be required? etc.”
She added: “The beauty behind these new working arrangements is we have two council speaking with one voice and that new voice is looking towards realigning priorities in line with our key strategic needs.”
The Brexit conference was told that the two neighbouring councils in Derry and Donegal complimented each other due to their differing attributes and make-up.
In Donegal there is a higher dependency on farming and agriculture with a labour force of 15,500 people, compared to the 3,341 in Derry-Strabane working in the industry.
“They are complimentary regions,” Loretta McNicholas said. “In Derry-Strabane the urban rural split is 71% urban, 29% rural, in Donegal is it is 19% urban and 81% rural.”
Michael Gallagher meanhwile said that 70% of dairy products from the north cross the border into the south for processing, while similary “an awful lot of beef goes north from the Republic.”
Over 40% of the population across Donegal, Derry and Strabane are aged under 40.
Population wise, the two council areas have total of 308,000 people, with a noticeable growth rate over the past 10 years, and a critical mass estimated at around 25% more that the current population (400,000).
The conference was told that the combined physical area of the two councils was 6,000 sq kms, 4,800 sq kms of it in Donegal and rest in Derry and Strabane.
Derry & Strabane and Donegal share a land boundary of 68 miles, with 50 different border crossing points along that.
Delegates at the conference were told that in terms of tourism revenue for Donegal, in 2015, 39% of revenue came from Britain, making it the most important sector. In Derry, there is also strong reliance on visitors and revenue from the Republic.