|A small family group whose homeland was in the English Middle March, in the Kelso region.|
Cessford Castle, or rather what is left of it, is in Roxburghshire, about 7 miles due south of Kelso. It was the seat of the Kers of Cessford,(one R) a family of nobility, who often, over the years, held high official positions. One was Warden of the Scottish Middle March. Their descendents still exist and the chief is Duke of Roxburghe and he now lives at Floors castle, near Kelso.
There was another group of the family, the Kerrs (two r's), whose seat was at Fernihirst Castle. The two groups were mostly at deadly feud with each other. They often killed each other but they also intermarried. The chief of this group is the Marquis of Lothian.
While their day job was being government officials maintaining the rule of the law, many did a bit of reiving on the side.
As so often happened, a village sprang up (for protection and trade) beside the castle. The villagers were known as, e.g., Thomas of Cessford, Liam of Cessford, and so on (like the German von). Later the 'of' was dropped and there came a time when surnames were needed when the government levied a poll tax. And so we would have a group of people with the surname 'Cessford.' Almost certainly, the villagers would be caught up in reiving activities being in close proximity of the Border.
Some Kers are very likely to have intermarried with the villagers of nearby Cessford village (marked on Ordnance Survey map west of the castle). So, conceivably, in theory, anyone with the surname Cessford could be related to the Duke of Roxburghe.