Kewu Plain, also known as Prambanan Plain or Opak River Valley, is a fertile volcanic plain that lies between the Merapi-Merbabu complex in the north, the Bantul lowlands and Sewu karst limestone range in the south, Bengawan Solo river valley in the east, the Progo River in the west, and Kedu Plain on the northwest. It is located within the Yogyakarta Special Region,[1] Sleman Regency, Klaten Regency, and Solo City (Central Java), Indonesia.
Historically the area was identified as Mamratipura. The region was the center of both the Mataram kingdom in the 8th to 10th centuries, and later the Mataram Sultanate in the 16th century. It has been an important location in Central Javanese history and culture for over a millennium since it contains many ancient archaeological remnants of historic significance. If each temple structure was counted separately, the 9th century Central Java period could be said to have produced thousands of temples, scattered from Dieng Plateau, Kedu Plain to Kewu Plain.[2]