Ostroh is a historic city located in Rivne Oblast of western Ukraine, on the Horyn River. Ostroh is the administrative center of the Ostroh Raion. Administratively, Ostroh is incorporated as a city of oblast significance and does not belong to the raion. Population: 15,195
The Ostroh Academy was established here in 1576, the first higher educational institution in modern Ukraine. Furthermore, in the 16th century, the first East Slavic books, notably the Ostrog Bible, were printed there.