The first Bunkle Castle was probably built in the 11th or 12th centuries, when a Norman knight was granted land at Bon Cill (meaning “chapel at the foot of the ridge”) and took the name de Bonkyll.

The establishment of a castle at Bunkle is commemorated in a traditional Berwickshire song:

Bunkle, Billie and Blanerne
Three castles strong as airn
Built when Davy was a bairn;
They’ll a’ gang doon
Wi’ Scotland’s croon,
And ilke ane shall be a cairn.

The castles referred to are Bunkle Castle, Billie Castle and Blanerne Castle, and the Davy mentioned is David I, which suggested all the castles were in existence by the late 11th century.

The site of Bunkle Castle is a natural knoll, rising from the surrounding land as it falls away to the south-east from the ridge of Bunkle Edge. The centre of the knoll was levelled and encloses an approximately circular area of around 57 metres in diameter.

The edges of the knoll were artificially built up with a bank of earth and stones, and a ditch or moat was dug on the outside to the north, west and south. A break in the scarp to the south-east may indicate an entrance, but the main approach seems to have been via a causeway to the north-west.

Outside the ditch to the north-west are slight traces of an outer bank, probably representing extra defences for the main entrance. It is within the north-west section of the site that the most masonry remains, possibly suggesting this was the strongest part of the castle on the most approachable side.

A massive corner section of wall stands close to where the entrance might have been, and measures around 4 metres wide and 4 metres tall, with walls around a metre thick.

A small, low window pierces the chunk of masonry.

On the south-west edge of the site a section of the curtain wall survives, measuring around 20 metres long and around 1.6 metres thick. It stands to a height of between 1.2 and 1.6 metres, but is now quite overgrown.

The earliest records to mention Bunkle Castle show it to be in the possession of Sir Alexander de Bonkyl in the 13th century. In 1288 his daughter, Margaret, married John Stewart, the son of Alexander Stewart, the 4th High Steward of Scotland, and Bunkle Castle passed into the Stewart family.

One of their grandsons, John Stewart of Bonkyll, son of Alexander Stewart of Bonkyll, would later become the 1st Earl of Angus in 1329. As a result of an illicit affair between Margaret Stewart, Countess of Angus and Mar, and her brother-in-law William Douglas, the 1st Earl of Douglas, in the 14th century, the Earldom of Angus passed to the Douglas family, as did Bunkle Castle.

In 1544 Bunkle Castle was destroyed by the Earl of Hertford during the Rough Wooing, and it is unclear whether or not it was ever rebuilt. The Douglas family owned various other castles and houses, so it is more than likely that they focused their attention elsewhere.

When Lady Lucy Montagu Douglas married Cospatrick Alexander Home, the 11th Earl of Home, in 1832, Bunkle Castle became the property of the Douglas-Home Earls of Home.