thumb|Location of Sanbu District in [[Chiba Prefecture]]
is a district located in Chiba Prefecture, Japan. As of January 2013, the district had a population of 49,488 and a population density of 369 persons per km<sup>2</sup>. The total area is .
Towns and villages
- Kujūkuri
- Shibayama
- Yokoshibahikari
Elevation of Ōamishirasato to city status
Ōamishirasato, formerly a town in Sanbu District, was elevated to city status on January 1, 2013, and is no longer part of Sanbu District.
History
During the early Meiji period establishment of the municipality system on April 1, 1889, the districts of with 3 towns and 14 villages, and with 1 towns and 14 villages were created in what was formerly the north-eastern portion of Kazusa Province. The two districts were formally merged into the new Sanbu District on April 1, 1897.
Mergers
- On March 27, 2006, the towns of Sanbu, Naruto, Hasunuma and Matsuo merged to form the new city of Sanmu.
- On March 27, 2006, the town of Yokoshiba merged with Hikari from Sōsa District to form the new town of Yokoshibahikari in Sanbu District.