The Eparchy of Lutsk–Ostroh (Lutsk–Ostroh of the Ukrainians) was a suffragan eparchy of the Metropolis of Kiev, Galicia and all Ruthenia in the Ruthenian Uniate Church and the Ukrainian Greek Catholic Church. It was situated in the Polish–Lithuanian Commonwealth (1594-1636, 1702-1795 and 1789-1839). Later, it was an Eastern Catholic titular see from 1921 to 1973.Ukrainian Greek Catholic Church at Encyclopedia of Britannica
