Although tradition says that the Kerrs were of Norman descent, from two brothers who settled in Roxburgh in the Scottish Borders in the 14th century, the name existed as early as the 12th century. It is also suggested that the name came from a Celtic word meaning strength. Whatever the origins, the families of Kers at Cessford and Ferniehurst became a powerful Border family, having been granted land in Roxburgh by James IV. Sir Robert Cessford became Lord Roxburghe in 1600 and in 1616 was elevated to Earl of Roxburghe. When Sir William Drummond, from another powerful Scottish family, married the Earl's daughter, he became the 2nd Earl and assumed the name of Ker. After supporting the Act of Union in 1707, the 5th Earl became Duke of Roxburghe. The direct line failed and, after a long dispute over who was next in line, Sir James Innes succeeded and became the 5th Duke. Another Kerr family was established in Lothian and the first Earl of Lothian was created in 1606.
There is a legend that the Kerrs were frequently left-handed and even constructed the spiral staircases in their castles so that they could take advantage over right-handed swordsmen. The term "Corrie-fisted" or left-handed is said to derive from this. But there is little in history to support the legend - the story is likely to have derived from the Gaelic "caerr" meaning "left".
Kerr was the 31st most frequent surname at the General Register Office in 1995.
The motto of the Kerrs is "Sero sed serio" ("Late but in earnest").
