The Rayen Castle (Persian: ارگ راين Arg-e Rāyen) is a historic adobe fortress situated on the outskirts of the Hezar Masjed Mountains, about 100 kilometers south of Kerman, Iran.

The castle and the mudbrick city it protects display numerous architectural elements and design strategies recognized as hallmarks of Iranian citadels.

Although believed to be at least 1,000 years old, it may have foundations dating to the pre-Islamic Sassanid era, with later additions and renovations during the Islamic period.

During the reign of the Sassanian king Yazdegerd III, the Arabs failed to conquer the city presumably due to its high walls.

[1] Today, Rayen Castle is a popular tourist destination, with efforts being made to preserve its cultural significance and secure its proposed inclusion on the list of UNESCO World Heritage Sites.