Schloss Buonas, Medieval castle on Lake Zug peninsula, Switzerland

Schloss Buonas is a medieval castle built on a small peninsula that juts into Lake Zug in the canton of Zug, Switzerland. The complex is made up of a rectangular courtyard, a recessed tower, and limestone foundations that sit right at the water's edge.

The earliest written record of the site dates to January 1130, when a charter mentioned the knights of Bochunna as the local rulers. Over the following centuries the estate changed hands several times before Hoffmann-La Roche took ownership in 1997.

Schloss Buonas is owned by the pharmaceutical company Roche and used as a private training center, so public access is restricted. The building can still be seen from the lakeshore paths, where its position at the water's edge makes it easy to spot.

The castle is private property and not open to the general public, but it can be seen from the walking paths along the lakeshore around the peninsula. A walk along the water gives a good view of the complex without needing to enter the grounds.

The neo-Gothic New Castle Buonas, designed by English architect William Wilkinson and built between 1873 and 1877 for Carl August von Gonzenbach-Escher, was demolished in 1970, not 1979. Owner Annie Bodmer-Abegg argued it could no longer be run economically; the canton's building department accepted this despite protests from the federal monument commission. The loss led Zug to appoint a full-time heritage conservator.