Emperor Suinin
Ninomiya was the location of the second-highest ranked shrine in Sagami Province, Kawawa Shrine, which is mentioned in Heian period records, and claims to have been established by the semi-legendary Emperor Suinin. As a minor coastal settlement, it was under the control of the later Hōjō clan of Odawara during the Sengoku period. In the Edo period, it was nominally part of Odawara Domain. After the Meiji Restoration and with the establishment of the district system in 1878, the area came under the control of . In April 1889, Ninomiya village merged with four neighboring hamlets to form Azuma with the establishment of the modern municipalities system, and on March 26, 1896 Yurugi District became part of modern Naka District. Azuma was elevated to town status on November 3, 1935 and was renamed Ninomiya.