Ostrov (Russian: ) is the name of several inhabited localities in Russia. The classification system of the types of inhabited localities in Russia, the former Soviet Union, and some other post-Soviet states has certain peculiarities compared to the classification systems in other countries. During the Soviet time, each of the republics of the Soviet Union, including the Russian SFSR, had its own legislative documents dealing with classification of inhabited localities. After the dissolution of the Soviet Union, the task of developing and maintaining such classification in Russia was delegated to the federal subjects.