Ostroh (Ukrainian: Остро́г; Russian: Остро́г, Ostrog, Polish: Ostróg) is a historic city located in Rivne Oblast (province) of western Ukraine, located on the Horyn River. Ostroh is the administrative center of the Ostroh Raion (district) and is itself designated as a special administrative subordination within the oblast. The current estimated population is around 15,202 (as of 2007). The Ostroh Academy was established here in 1576, was the first higher educational institution in current Ukraine.