Brunegg Castle was built in the first half of the 13th century as a base for the Habsburg officers. It's first owner, mentioned in 1270, was Wernher dem Schenken von Brunegg. A deep moat and a four-meter wall completely safeguarded the main part of the castle completely against attacks. In the 14th century several other Habsburg-Austrian officers owned the castle before it was partially destroyed by fire in 1375. In the course of the subsequent reconstruction work, a tower was added to reinforce the castle, probably initiated by Heinrich Gessler.
Under the rule of Berne. After the area of Aargau was conquered by the Swiss the castle belonged to Berne. In 1473 it was given as a fiefdom to the Segens family and in 1538 to the reeve of Lenzburg. A sentry was posted at the castle to secure and keep watch over the borders of Berne’s territory. After having been a seat of nobility, the Brunegg castle and its outlying farms then became a part of Berne’s defensive system. The castle underwent several renovations in the 16th and 17th centuries. It was struck by lightning in 1555 and again in 1627. Another lightning strike in 1664 caused the black powder stored in the main tower to explode. Twenty years later the tower imploded completely. While the tower was left as a partial ruin, everything else was subsequently restored.
Hünerwadel and von Salis. After the collapse of the Ancien Régime, a private individual turned the castle into a hospital. The remains of the tower were partly removed, the main castle was put under one roof and garden terraces were built for the sake of greater comfort and convenience. Having failed as a hospital, the castle was taken over by the family.