Qasr al-Azraq (Arabic: قصر الأزرق‎, "Blue Fortress") is a large fortress located in present-day eastern Jordan. It is one of the desert castles, located on the outskirts of present-day Azraq, roughly 100 km (62 mi) east of Amman.Its strategic value came from the nearby oasis, the only water source in a vast desert region. The name of the fortress and associated town came from these.