Chiba Prefecture was established on June 15, 1873 with the merger of Kisarazu Prefecture and Inba Prefecture.
Chiba borders Ibaraki Prefecture to the north at the Tone River, Tokyo and Saitama Prefecture to the west at the Edo River, the Pacific Ocean to the east and Tokyo Bay around its southern boundary.
On March 27, 2006, the towns of Hikari from SousaDistrict and Yokoshiba from SanbuDistrict merged to form the new town of Yokoshibahikari in SanbuDistrict.