At their closest point, only 13 miles of water separate the coasts of Ulster and Scotland. From the earliest times to the present day there has been a constant flow of people and ideas between the two coasts.

Geography and history have combined to link the peoples of Scotland and Ulster closely together. Indeed, some people have viewed Ulster as an extension of Scotland. With equal logic, Scotland might be viewed as an extension of Ulster.

The most important migration across the North Channel was the early 17th-century Plantation of Ulster. It has proved to be one of the most politically significant mass migrations to have taken place in western Europe since medieval times but it also should be viewed as part of a well-established pattern of population movement between Ulster and Scotland.