Üsküdar, former city, northwestern Turkey, now a district of Istanbul. It lies at the foot of the Bulgurlu Hills on the Asiatic side of the Bosporus Strait opposite central Istanbul. Known as Chrysopolis in ancient times, it was a dependency of the older and better-sited colony of Chalcedon (modern Kadıköy), where, according to the historian Polybius, the Athenians set up a toll for ships passing through the Bosporus. The name Scutari came into use toward the end of the Byzantine period. The Ottoman Turks took the city in the 14th century and renamed it Üsküdar (“Courier”) because of its function as a post station for Asiatic couriers. The Ottomans used it as a base for military operations and also, until the development of the Anatolian railways, as the terminus of caravan routes from Syria and Asia.
Üsküdar, as seen from the sea, presents a view of painted wooden houses and white minarets backed by the cypress trees of its great cemetery, Büyük Mezaristan, which lies farther inland. The cemetery includes the graves of 8,000 British soldiers who died there during the Crimean War (1853–56). The district’s major buildings include the Mihrimah (or Iskele) Mosque, built by the architect Sinan in 1548, the vast barracks of Sultan Selim III, and the military hospital made famous during the Crimean War (1853–56) by the pioneering nursing work of Florence Nightingale.
The Üsküdar district is primarily residential, and considerable numbers of its residents commute to central Istanbul. It is connected by rail and road with major centres of Anatolia and is linked by ferry service and bridge with central Istanbul.