Schloss Sigmaringen, also Hohenzollernschloss, marks the historical centre of the town of the same name as a former princely residence and dominates the Donautal on the southern edge of the Schwäbischen Alb.
The complex sits atop the elongated limestone outcrop of the Weißjura, the so‑called Schlossberg, which stretches for about 200 metres and rises up to 35 metres above the Donau. The plateau lies within the landscape of the Naturpark Obere Donau at roughly 605 metres above sea level; the Donau itself is at about 570 metres. The exposed position explains its original importance as a medieval defensive stronghold.
The history of the building dates back to the 11th century; a castle complex is first mentioned in connection with a siege in 1077. In the 12th and 13th centuries a new construction was carried out using bossed ashlar masonry. Changes of ownership and phases of expansion under regional comital families shaped its growth into a palace complex. In the 16th century the House of Sigmaringen passed to the House of Hohenzollern; since then the castle developed as the residence of the Hohenzollern‑Sigmaringen line. War damage, fires and repeated alterations determined the architectural development from the Baroque period into the 19th century, when extensive representative buildings and attractive interiors were created. A severe fire in 1893 destroyed large parts of the east wing; the affected area was rebuilt and stylistically redesigned into the early years of the 20th century. During the final months of World War II, in 1944/45, the castle served as an exile location for French Vichy politicians; the seizure ended in 1951 and the estate returned to the princely family. Since the end of the 20th century parts of the castle have again been used as a residence and for administration; the ensemble remains a museum.
The present collections and exhibitions reflect this history: historic state rooms furnished with furniture, paintings and porcelain convey courtly life. The weapons collection comprises around 3,000 objects and is one of the most extensive private holdings in Europe; it documents developments from the Middle Ages to the 20th century and, alongside European armour, also displays non‑European pieces. The gallery wing housed the Fürstliches Museum with significant works of Swabian art as well as a pre‑ and early‑historical collection, whose archaeological holdings were transferred to the Landesmuseum Württemberg in 2022. The Marstall building presents the princely vehicle collection with carriages and court equipment. The princely court library in the Wilhelmsbau preserves around 200,000 volumes and extensive archival and manuscript holdings.