Specific counties surrounding the Irish Sea and part of its “Cultural Region.”
Ireland–Derry/Londonderry, Down, Armagh, Antrim, Tyrone. These counties are the core of Northern Ireland.
Scotland–Ayr, Dumfries, Wigtown, Roxburgh, Berwick. These ancient counties were often called The Marches and ruled under military jurisdiction.
England–Cumberland, Northumberland, Durham, Yorkshire (East Riding), Westmoreland, Lancashire (west of the Pennines). These peoples were often called the Borderers.
This fairly rich, central and northern lowlands provided good agricultural lands that supported a dense population. The population was mostly Protestant, especially Presbyterian. And they shared dislike and even hatred of the English who dared to rule them with alternating freedom and severe limits. Your favorite genealogist, Arlene Eakle http://arleneeakle.com
PS Still looking for a map of the Irish Sea. Stay tuned.