Altaş Castle, locally known as Altaş Kalesi, lies atop a somewhat circular hill on the northern bank of the river Kura, next to the village with the same name, in the province of Ardahan in Turkey. The village of Altaş was also known as Ur. So the castle would probably also have been known as Ur Castle.
When Altaş Castle was exactly built is unknown. In ancient sources it is only mentioned by name and location. But around the castle, remains of settlements dating back to the 7th and 8th century were found, so it is believed that the castle was also built somewhere in that period. It probably used to control a location where the road to the north, to Hanak, crossed the river.
I was not able to find any historical information about this castle. If you know more, please mail me.
The ruin of Altaş Castle has a circular plan with a circular keep at the southern side, a design I haven't seen in any other castle in this area. The entrance seems to have been opposite the keep. There were foundations of 3 wall towers in the wall on the eastern side.
At present Altaş Castle is freely accessible. Not a very spectacular ruin but interesting because of its unique plan.