Schloss Heerbrugg, Château in Heerbrugg, St. Gallen, Switzerland

Schloss Heerbrugg is a castle on the Hümpeler ridge above the Aich stream, built in 1775 by St. Gallen merchant Bartholomäus Schlumpf. The main building is a plain residential block; its onion-domed tower was added only in 1911. Next to it stands the Villa Schmidheiny, built in 1910 for Ernst Schmidheiny, and a small gatehouse at the start of the servants' path.

A Roman-era fort is thought to have stood on the Hümpeler ridge above the Aich bridge before Abbot Ulrich III of St. Gallen built the Hêrburch there in 1077/1078. That fortress was destroyed around 1280 and the estate lay abandoned. A fire destroyed the farm on 13 February 1774; Bartholomäus Schlumpf bought it and rebuilt the present Schloss in 1775, without today's tower.

The name Heerbrugg derives from "Herrenbrugg über die Aich", the form recorded in a 1518 deed marking the boundaries between Lustenau, Berneck, Balgach and Kriessern. The Aich was a side arm of the Rhine that regularly flooded the valley floor in heavy rain. Since 2006 the castle has belonged solely to Peter von Rotz, who kept the name rather than rename it.

Schloss Heerbrugg stands on the Hümpeler ridge above the Aich, on the Heerbrugg foothills of the Balgacher Berg. The tower with its onion dome was added in 1911, so the silhouette seen from the valley dates from that renovation. The building is privately owned since 2006 and not open as a museum; the neighbouring Villa Schmidheiny houses a wine cellar with a 1999 extension used for tastings.

The tower with its onion dome was only added in 1911, when Jacob II Schmidheiny rebuilt the castle; his brother Ernst had the neighbouring Villa Schmidheiny built for his own family. Locals still call the building Schloss Schmidheiny, after the villa, though owner Peter von Rotz, who bought it in 2005 and has held it alone since 2006, declined to rename it.