Greenlaw Castle, the site of which is marked by a solitary tree in a field to the east of the village of Greenlaw, is said to date back to the 13th century.

The settlement of Greenlaw may date back as far as the 10th century, and in the second half of the 11th century the barony of Greenlaw came into the possession of Cospatric III, the 2nd Earl of Lothian.

The lands of Greenlaw passed from Cospatric III to his second son Patrick, and on to Patrick’s son William de Greenlaw, who is said to have built Greenlaw Castle early in the 13th century.

William married his cousin, Ada, daughter of Patrick, the 4th Earl of Dunbar. This was Ada’s third marriage, having previously been married to William de Courtenay and Theobald de Lascelles. Upon her fist marriage to Courtenay, Ada’s father gave her the barony and castle of Hume. From Ada and William are descended the great Border family of Home.

In 1451 or 1452 the lands of Greenlaw were made into a free barony by James II, and granted to Thomas de Cranston of Cranston, from whom they passed to the Redpath family around 1470. In 1598 the barony of Greenlaw returned to the Home family when WIlliam Redpath entered into a bond with Sir George Home of Spott, transferring the barony to him.

Following Sir George’s death in 1611 the barony of Greenlaw passed via his daughter, Anne, wife of Sir James Home of Coldingknowes, to his grand-nephew, Sir Alexander Home of Manderston. When he had financial difficulties after the Restoration, Greenlaw Castle and barony were confiscated from him by his creditors.

In Joan Blaeu’s Atlas of Scotland, published in 1654 but based in part on Timothy Pont’s maps of the late 16th to early 17th century, Greenlaw Castle is shown as a substantial building surrounded by trees.

Some time between 1688 and 1696, Sir Patrick Hume of Polwarth bought back the possessions of the Homes of Spott.

Greenlaw Castle continued to be occupied by the Hume family until 1729, after which it was used as accommodation for farm labourers. Around 1820 it was largely demolished, although a small section of wall survived into the 1850s before finally being removed and ploughed over. Today all that remains is a slight mound in the field and a large ash tree.