Gretna is a town in Dumfries and Galloway, Scotland, originally part of the historic county of Dumfriesshire. It is located close to the A74(M) on t…Gretna is a town in Dumfries and Galloway, Scotland, originally part of the historic county of Dumfriesshire. It is located close to the A74(M) on the border of Scotland and England and near the mouth of the River Esk.