The remains of the Castle can be visited
Upper-Ruchenberg Castle (Ruin) (Trimmis)

The ruin of Ober-Ruchenberg, a former fortress in the Swiss canton of Graubünden, stands on a wooded hill high above the hiking trail from Trimmis to Chur. It is freely accessible today.
History+
The first documented mention of Ruchenberg Castle dates back to 1328, when a priest named Arnold Sassin was slain in front of its walls. The Lords of Ruchenberg appeared in historical documents in the 13th century, including the knights Albero and Detrich de Ruhin-berg. In 1370, Johann von Ruchenberg killed his sister Katharina, which led to his feudal estates being assigned to the fortress of Trimmis. Although the Ruchenbergs still held episcopal meadows as fiefs in 1395, the castle itself was no longer in their possession, and the lineage presumably died out shortly thereafter. In the 15th century, the castle passed through various hands, including Dietegen von Marmels (1409) and a bailiff of the Lords of Sigberg (1444). In 1521, Ulrich von Schlandersberg pledged the Ruchenberg castle site, and in 1522, Josua von Beroldingen acquired the complex, which was probably already uninhabited at that time. Johannes Stumpf referred to it as a ruin in 1548.
Source: Wikipedia · Licence: CC BY-SA 4.0
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 46.8808, 9.5720