The Debatable Lands, also known as debatable ground, batable ground or threip lands, lay between Scotland and England. These lands were formerly in question to which it belonged, when they were distinct kingdoms. The name signifies the same thing as litigious or disputable ground.
The Debatable Lands extended from the Solway Firth near Carlisle to Langholm in Dumfries and Galloway, the largest population centre being Canonbie. The lands included the baronies of Kirkandrews, Bryntallone and Morton. They were around ten miles (16 km) long from north to south and four miles (6 km) wide. The boundaries were marked by the rivers Liddel and Esk in the east and the River Sark in the west. For over three hundred years they were effectively controlled by local clans, such as the Armstrongs, who successfully resisted any attempt by the Scottish or English governments to impose their authority. In his history of the Border Reivers (The Steel Bonnets (1971)), George Macdonald Fraser says that the Armstrongs alone could put 3,000 men in the field. They launched frequent raids on farms and settlements outside the Debatable Lands, the profits enabling them to become major landowners. Other clans in the area were the Elwands, Ellwoods, or Elliots who extended into Teviotdale; the Nixons who were more numerous in Cumberland; the Crossars in Upper Liddesdale, with their chief stronghold in Riccarton/Riccarton Mill (Rickerton, forms of Richardtown) Northern/Upper Liddesdale (listed in valleys of Liddesdale as locus/locality of Croyser 1376) of Hudhouse also located nearby on Liddel (It is a mistake to suppose they settled in Debatable lands on the lower Liddel though at Riccarton, and Hudhouse they were on the upper end of the Liddel Water.)and the Grahams, who owned five towers in the Debatable Land. The Irvings, Olivers, Bells, Dicksons, and Littles were also present in varying numbers.