Burg Rosenegg, Medieval castle in Bürs, Austria.

Burg Rosenegg is a small medieval hilltop castle on the easternmost spur of the Schaß at 623 m above sea level, southeast of Bürs. It consists essentially of a five-story bergfried and an adjoining perimeter wall, with original fabric surviving only in the foundation area. The tower's high rectangular windows and tent roof date from a 1939 renovation.

Burg Rosenegg was built in the mid-13th century by the Counts of Werdenberg-Heiligenberg and was initially part of the County of Sonnenberg. In 1405, during the Appenzell War, it was destroyed by Walgau forces allied with the Appenzellers. After passing to Austria in 1418/1420 it was granted as an Austrian fief, and in 1474 the lordship was merged with Bludenz; the castle fell into ruin before 1600. The bergfried was rebuilt in Neo-Gothic style between 1898 and 1900, then altered again in 1939, when the Neo-Gothic elements were removed, a fifth storey and a tent roof were added, and a single-storey house was built against the tower.

The castle once served as a seat of local noble families and shaped the region's medieval character. Today it remains a visual anchor in the landscape, reminding visitors of the feudal past of Vorarlberg.

The castle interior is not open to the public as it remains privately owned, but visitors can walk the Rundweg Biotop Schloss Rosenegg trail that circles the exterior. This path provides clear views of the structure and the surrounding landscape.

The castle rests on a distinctive rocky base made of Bürser Konglomerat, consolidated gravel deposits from the Alvier stream. This geological formation gave the site unusual stability and durability for medieval construction.