Adalar, also known as the Princes' Islands or the Princes' Archipelago, is an archipelago consisting of nine islands located off the coast of Istanbul, Turkey, in the Sea of Marmara. These islands constitute a specific municipality and district within the Istanbul Province.
The district covers a total land area of 11 km2 (4.2 sq mi), making it the fifth smallest district in Istanbul. With a permanent population of 16,690 as of 2022, Adalar is by far the least populous district in the city.