Wat Kasatrathiraj Warawihan is a third-class royal monastery categorized as a Wora vihara, located by the Chao Phraya River in Phra Nakhon Si Ayutthaya District, just outside the western side of the old city, across from Wang Lang or Suan Luang Palace. Originally known as "Wat Kasatra" or "Wat Kasatram," this ancient temple was built during the time when Ayutthaya was the capital. The main feature of the temple is its prang (spire). During the reign of King Rama I, Prince Anurak Teves do and Prince Isranurak (Khet) undertook a restoration of the entire temple complex.