On November 1, 2004 - the town of
Jūō (from
Taga District) was merged into the expanded city of Hitachi.
Taga District was dissolved as a result this merger.
On September 12, 2005 - the old city of
Koga absorbed the towns of
Sanwa and
Sōwa (both from
Sashima District) to create the new and expanded city of Koga.
On October 1, 2005 - the old city of
Ishioka absorbed the town of
Yasato (from
Niihari District) to create the new and expanded city of Ishioka.
On October 11, 2005 - the town of Hokota absorbed the villages of
Asahi and
Taiyō (all from
Kashima District) to create the city of Hokota.
Kashima District was dissolved as a result of this merger.
On January 1, 2006 - the town of
Ishige (from
Yūki District) was merged into the expanded city of Mitsukaido. Mitsukaido changed the name to Jōsō at the same time.
On November 1, 2004 - the town of
Jūō (from
Taga District) was merged into the expanded city of Hitachi.
Taga District was dissolved as a result this merger.
On September 12, 2005 - the old city of
Koga absorbed the towns of
Sanwa and
Sōwa (both from
Sashima District) to create the new and expanded city of Koga.
On October 1, 2005 - the old city of
Ishioka absorbed the town of
Yasato (from
Niihari District) to create the new and expanded city of Ishioka.
On October 11, 2005 - the town of Hokota absorbed the villages of
Asahi and
Taiyō (all from
Kashima District) to create the city of Hokota.
Kashima District was dissolved as a result of this merger.
On January 1, 2006 - the town of
Ishige (from
Yūki District) was merged into the expanded city of Mitsukaido. Mitsukaido changed the name to Jōsō at the same time.