Khornabuji Castle, Medieval fortress on the Tsiv-Gombori ridge in Kakheti, Georgia

Khornabuji Castle is a ruined stone fortress perched on a mountain ridge in the Kakheti region of Georgia, above the valleys of the Alazani and Iori rivers. What remains includes sections of thick walls and several towers built directly into the rocky terrain.

The fortress dates back more than two thousand years and served from early on as a defensive post on Georgia's eastern frontier. It was reinforced in the 5th century under King Vakhtang I and remained a strategic point for many centuries after.

The name Khornabuji derives from the Persian words for sun (khvaran/khoran) and mountain (ta), meaning 'sun mountain'; the scholar Alexandre Ghlontishvili instead linked buji to the Georgian word for tower, giving 'tower of the sun idol'. Locals call the site Tamaris Tsikhe, the Fortress of Tamar, after Queen Tamar. In the 17th century the castle was also known as Choeti.

The ruins sit on a rocky ridge and can only be reached on foot, so sturdy footwear is strongly recommended. The climb is steep, so bringing enough water and starting in the cooler morning hours makes the visit more manageable.

Excavations in the 1970s uncovered the remains of a medieval settlement at the base of the fortress walls, showing that this was once a lived-in community, not only a military post. This means the site held both soldiers and ordinary residents going about daily life.