Traditionally the Kerrs were of Anglo-Norman origin and descended from two brothers who settled in Roxburgh in the 14th century, but it is also claimed that the name is derived from a Celtic word meaning strength. The names Ker, Kerr and Carr were common on the borders.

The Kers of Cessford were wardens of the marches and prominent in Border conflicts. They were granted old Roxburgh by James IV., and Sir Walter of Cessford fought on the side of James VI. At Langside in 1568. Sir Robert, born in 1570, was created Lord Roxburghe in 1600, and in 1616 was elevated to the Earldom of Roxburghe and appointed Lord Privy Seal in 1637. By Marriage with the Earl’s daughter Jean, Sir William Drummond became 2nd Earl of Roxburghe and assumed the name Ker. John, 5th Earl, supported the Union of 1707, and was created Duke of Roxburghe. John, 3rd Duke, was a noted book-collector, and the sale of his library was a famous event in the literary world. The direct line having failed, Lord Bellenden became 4th Duke, and his death without surviving issue led to a long and confused contest. Sir James Innes succeeded as 5th Duke and assumed the name Ker.

Mark Ker was abbot of Newbattle in 1547, and his son Mark had the lands of Newbattle erected into a barony in 1587 and in 1606 he was created Earl of Lothian. His son Robert, 2nd Earl, had no male issue, and the title passed through his daughter to her husband William Ker, son of the 1st Earl of Ancrum, who became 3rd Earl of Lothian in 1631. Robert, 4th Earl, was raised to the Marquessate of Lothian in 1701. The Kers are numerous in Arran.

Crests: A unicorn’s head erased argent, armed and maned; or, A boar’s head erased proper, langued gules. The sun in his splendour.