Burg Straußberg, Medieval castle in Sondershausen, Germany.

Burg Straußberg is a spur castle on a 390 m hill spur of the Dün ridge within the village of Straußberg, part of Sondershausen in the Kyffhäuserkreis. Its trapezoidal ground plan, including the ditch, measures about 70 × 70 m. The oldest part is the round keep projecting from the wall front on the south side, built of small rubble stones with few window slits and a high entrance once reached by ladder; its platform, now used as a viewpoint, has no battlement, though a 19th-century picture shows a tall conical roof with weather vane. The gatehouse on the south side is a ruin, the palas with the living quarters stood on the north side of the courtyard, and the castle chapel lies west of the tower.

The castle was founded around 1200 by Thuringian landgraves and changed hands several times over the centuries. In 1552 it became the residence of Count Wilhelm von Schwarzburg, marking an important phase in the site's role as a seat of local power.

The castle chapel west of the keep was restored around 1870; only the choir survived as the chapel, while the owner used the drier nave to store grain. Three odd stones stood in the chapel's anteroom, shaped like official hollow measures in which grain from wooden bushels was poured to check them.

The keep can be climbed and serves as a viewpoint, but the buildings are a partly consolidated ruin; visits to the buildings are arranged through the local castle association. The site lies on a 390 m spur of the Dün within the village of Straußberg, about 16 km north of Schlotheim.

Three odd stones stood in the chapel's antechamber, resembling old official hollow measures used to test wooden grain scoops (Scheffel): grain was poured into the hollows, and a scoop that underfilled them was destroyed to prevent fraud. The castle housed a Schwarzburg-Rudolstadt office until 1850, whose administrator had to keep various standard measures.