Negiuchi Castle, Japanese castle in Negiuchi, Japan

Negiuchi Castle is a Japanese castle in Negiuchi, Matsudo, Chiba Prefecture, built on a peninsula-shaped plateau tip between two valleys cut by tributaries of the Fuji River. Its southern connection to the plateau was cut by a dry moat, and the interior was divided into about six enclosures around the area near the castle's inner section. From the main gate (otemon), dry moat and earthen rampart traces survived until recent times about 300 m to the southeast, suggesting the castle extended further south, with a north-south extent of 600 m. Between the otemon enclosure and the main enclosure were a small enclosure and, between that and the main enclosure, an umadashi enclosure; protruding turret platforms (yagura-dai) guarded the otemon, the small enclosure's gate and the umadashi enclosure, facing the southern plateau connection.

Built in 1462 by Takagi Tanetada, according to the Takagi family documents, though a tradition credits Takagi Taneyoshi with founding it in 1508. It replaced Kurigazawa Castle as the Takagi base until the family moved to Kogane Castle in 1537. The earthworks were cut off by dry moats, and traces of a dry moat and embankment survived until recently about 300 m southeast of the main gate.

The site served as a central point for controlling the surrounding region and managing local affairs. People living nearby organized their lives and work around the presence of this defensive stronghold.

The ruins can be explored on foot, allowing visitors to examine the preserved walls and fortifications up close. Sturdy footwear is recommended since the grounds are uneven and some areas may become muddy after rain.

The castle occupied the tip of a peninsula-shaped plateau cut by valleys on its east and west sides; the southern link to the plateau was blocked by a dry moat. The site is now split by National Route 6: the northwest half was lost to housing, while the southeast half opened on 22 April 2006 as Negiuchi Historical Park.