Ōshū is a city located in Iwate Prefecture, Japan. As of 30 April 2020, the city had an estimated population of 114,620 and a population density of 120 persons per km² in 45,728 households. The total …Ōshū is a city located in Iwate Prefecture, Japan. As of 30 April 2020, the city had an estimated population of 114,620 and a population density of 120 persons per km² in 45,728 households. The total area of the city is 993.30 square kilometres. Ōshū is famous for its Maesawa Beef, numerous festivals, historic temples and shrines and Fujiwara no Sato, a theme park and movie lot based on the exploits of the Northern Fujiwaras in the 12th century. Many famous people claim Ōshū as their home, including Ichiro Ozawa, the long-time leader of the Democratic Party of Japan.