The Nobel Peace Prize winner John Hume was the guest of honour at the launch in Donegal town this week of the Strabane and South Donegal Tourism Initiative.
The partnership between the two towns is part of a wider cross-Border scheme which will eventually involve up to 12 towns in twinning arrangements.
Funded by the EU's peace and reconciliation fund, the Border Towns Marketing Scheme is run under the auspices of Bord Failte and the Northern Ireland Tourist Board.
Mr Hume said that with political progress in the North, the potential was there to "transform" the economy of the Border counties.
"I hope that despite the difficulties in the peace process, we are leaving the quarrels of the past behind us," he said.
The scheme will be jointly run by Strabane District Council and Donegal Chamber of Commerce, which each received £20,000 of European funding.
Brochures and maps, a Donegal and Strabane Web site, direct mail campaigns and participation in trade shows are included in the promotion.
The campaign focuses on natural amenities along the 21-mile "corridor" between the two towns. There is also an emphasis on historical links with the United States. Since the ceasefires, all the Border roads between Donegal and Tyrone have reopened, so sign-posting has been improved.
At the launch Mr Ivan Barr, the chairman of Strabane District Council, said links between the two towns had existed for centuries and these links were important to the social and cultural fabric of the two communities.
Cross-Border co-operation on tourism continues to grow, but promotional literature for the Strabane-Donegal campaign is unlikely to please all unionists - the Border is omitted from a map of the area.