Borthwick Castle is one of the largest and best-preserved surviving medieval Scottish fortifications. It is located twelve miles (19 km) south-east of Edinburgh, to the east of the village of Borthwick, on a site protected on three sides by a steep fall in the ground. It was constructed in 1430 for Sir William Borthwick, from whom the castle takes its name,

Sir William Borthwick, 3rd of Borthwick and later 1st Lord Borthwick was a Scottish peer and ambassador.