is a town located in Nishiiwai District, Iwate Prefecture, Japan. , the town had an estimated population of 7,408 and a population density of in 2,616 households. The total area of the town was . It is noted for the Historic Monuments and Sites of Hiraizumi, which achieved UNESCO World Heritage Site status in 2011. Geography Hiraizumi is the smallest municipality in Iwate Prefecture in terms of area. Located in a basin in south-central Iwate Prefecture in the Tōhoku region of northern Honshu, the town is surrounded by the Kitakami Mountains. Neighboring municipalities Iwate Prefecture Ichinoseki Ōshū Climate Hiraizumi has a humid climate (Köppen climate classification Cfa) characterized by mild summers and cold winters. The average annual temperature in Hiraizumi is 10.8 °C. The average annual rainfall is 1265 mm with September as the wettest month and February as the driest month. The temperatures are highest on average in August, at around 24.4 °C, and lowest in January, at around -1.9 °C. Demographics Per Japanese census data, the population of Hiraizumi peaked around 1950, and has declined over the past 70 years. History The area of present-day Hiraizumi was part of ancient Mutsu Province. It was the home of the Northern Fujiwara clan for about 100 years in the late Heian era, during which time it served as the de facto capital of Ōshū, an area containing nearly a third of the Japanese land area. At its height the population of Hiraizumi reached 50,000 or more than 100,000, rivaling Kyoto in size and splendor. The first structure built in Hiraizumi may have been Hakusan Shrine on top of Mount Kanzan (Barrier Mountain). A writer in 1334 recorded that the shrine was already 700 years old. Although rebuilt many times, the same shrine is still standing in the same location. In about 1100, Fujiwara no Kiyohira moved his home from Fort Toyoda in present-day Esashi, in the city of Ōshū to Mount Kanzan in Hiraizumi. This location was significant for several reasons. Kanzan is situated at the junction of two rivers, the Kitakami and the Koromo. Traditionally the Koromo River served as the boundary between Japan to the south and the Emishi peoples to the north. By building his home south of the Koromo, Kiyohira (half Emishi himself) demonstrated his intention to rule Ōshū without official sanction from the court in Kyoto. Kanzan was also directly on the Ōshū Kaidō, the