The area of present-day Ichinomiya has been inhabited since prehistoric times. The area takes its name from the
Tamasaki Shrine, the
Ichinomiya, or first shrine of
Kazusa Province. During the
Sengoku period, the
Satomi clan, the virtually independent rulers of the Bōsō Peninsula, established a
castle at Ichinomiya. The area was devastated by the
1703 Genroku earthquake, during which a
tsunami extended 1.5 kilometers inland from the coast. During the
Edo period, a 13,000
koku feudal domain called
Ichinomiya Domain ruled the area. After the start of the
Meiji period, the area rapidly developed as a summer health resort, with many noted politicians, military figures, artists and writers establishing summer residences. Ichinomiya Town was created within Chōsei District with the establishment of the modern municipalities system on April 1, 1889. Ichinomiya merged with the neighboring village of Torami on November 3, 1953. ==Government==