Stickhausen Castle, Medieval castle in Lower Saxony, Germany.

Stickhausen Castle is a lowland castle on the Jümme at the western edge of Stickhausen, a district of Detern in the Leer district of East Frisia, Lower Saxony. Of the former fortress, only the large round tower, dated 1498, and remains of the ramparts survive. The tower stands on a site once enclosed by two moats and walls.

Hamburg built the castle around 1435 to protect its westbound trade routes; unlike other East Frisian castles it was never a chieftain's seat. Around 1453 the city pledged it to Ulrich I, who used it to replace the older Schlüsselburg border fortress at Detern. Count Edzard I added the round tower around 1498, and Countess Anna had a gun platform called the Dwenger built in 1558 from stones of Barthe Abbey. Prussia razed the fortress after 1744.

The name combines Sticke (pole) and Haus, meaning a house fortified with palisades. Since 2000 the grounds host the Burggarten Stickhausen garden market each June, and a local castle association founded in 2019 is setting up a museum in the round tower.

A visit works best in drier months since parts of the grounds are outdoors and can be harder to explore in wet weather. It is worth checking in advance which parts of the site are open to visitors before you travel.

The castle stands on the Jümme, not the Leda, at the point where the two rivers form the East Frisian Mesopotamia. The name Stickhausen comes from sticke (pole) and Haus, meaning a house fortified with palisades. The round tower served as a prison, and its ground floor still held the cells with a rack and clamps when a local heritage museum was housed there.