Mihara (三原市, Mihara-shi) is a city located in Hiroshima Prefecture, Japan. The city was founded on November 15, 1936.As of March 1, 2008, the city has an estimated population of 103,162 and a population density of 219 persons per km². The total area is 471.03 km².On March 22, 2005, the town of Daiwa (from Kamo District), the town of Kui (from Mitsugi District), and the town of Hongō (from Toyota District) were merged into Mihara.