Thirlwall Castle is a 12th-century castle in Northumberland, England, on the bank of The River Tipalt close to The Village of Greenhead and approximately 20 miles (32 km) west of Hexham. It was built in the 12th century, and later strengthened using stones from nearby Hadrian's Wall, but began to fall into disrepair in the 17th century. The site is protected by Grade I listed building and Scheduled Ancient Monument status.
The origin and meaning of "Thirlwall", is an old English word "Thirl" derived from the Greek "Thura" and more familiar English word "wall", related to nearby Hadrian's Wall.The name "Thirlwall" is often pronounced "Thura wall" (thoo-rah-wall). The root and meaning of the name "Thirlwall" is further understood by the following information provided in Strong's Enhanced Lexicon.