相模川
Kōza District was one of the ancient subdivisions of Sagami Province, extending from Sagami Bay north to the border of Musashi Province between the Sagami River and the Sakai River. It was mentioned in the "Nihon Shoki" records of 675 AD in the Nara period as . The provincial capital of Sagami Province and its "kokubunji" were located within Kōza District, although its exact location is today unknown.