The castle, which was built around a 14th century Pele tower given by King Robert the Bruce to the Earl of Moray, was bought for William Hay of Drummelzier by his father the Earl of Tweedale in 1696. The Hay family have lived there in unbroken succession ever since.
The Hays have considerably enlarged and embellished the building into its final Gothic Revival form, designed and completed by the celebrated architect James Gillespie Graham between 1818 and 1822.
Duns law on the estate is the historic scene of the Scottish Covenanters rising against King Charles 1 in 1639 under General Leslie, who was quartered in the Castle.
The first Mrs. Hay of Duns Castle was a descendant of Mary Seton, a lady-in-waiting to Mary, Queen of Scots, so the house has strong Stuart connections.