Boselt Castle, locally known as Boselt Kalesi or sometimes as Şerbiyet Kalesi or Kaleyle, lies on a rocky crag south west of the village of Okumuşlar, in the province of Artvin in Turkey.
When Boselt Castle was built is unknown, only that it was built by a Georgian king in memory of his daughter. The castle was accompanied by a settlement, on the site of the present village, that served as a trade center for the area. There are supposed to be underground tunnels in the rock beneath the castle.
At present Boselt Castle is inaccessible. That is to say; I could not find any safe path to it. Too bad, it looks very promising. If you are going to Okumuşlar be prepared for a long mountainous ride, because the short routes have been flooded because of the new reservoir already filling up.