The Ostrozac castle is located in the municipality of Cazin, about half way between Velika Kladusa and Bihac.
It is an impressive, huge, castle complex that dates back to the 16th century, just before the Turks invasion. The outer walls are more than 2 mt thick.

Though partially in ruins, the castle is open for visitors and there is a guard who sells entrance tickets for 1KM (=0.5 E).
I was the only visitor, but the castle is a popular place for young local couples looking for a bit of privacy...
The large inner garden is decorated with modern stone statues.
The main castle house is open and it is in a wonderful position, overlooking the Una river valley.