Burg Hopfen, Medieval castle in Füssen, Germany

Burg Hopfen is a medieval castle site in Füssen that sits on a hill overlooking Hopfen Lake, with walls preserved in places up to three meters in height. The excavations have uncovered distinct areas including living quarters and a chapel.

The castle's origins are unclear; it may be the "festes Burg" where Augsburg's rival bishop Wigolt took refuge in 1078 during the Investiture Controversy. From 1172 to 1191 a Welf ministerialis family held it and took its name. It then passed to the Hochstift Augsburg and served until 1322 as the seat of the Füssen provost. After the Hohes Schloss was rebuilt in Füssen in the 15th century, the castle became dispensable and fell into ruin.

The castle gave its name to a Welf ministerialis family that held it from 1172 to 1191. After passing to the Hochstift Augsburg, it served until 1322 as the seat of the Füssen provost. The name Hopfen also denotes the hamlet below the hill.

The ruin stands on a hill above the Hopfen am See district of Füssen. The exposed walls, up to three metres high, and the filled-in breaches can be reached on foot; the site is mainly visited for the view of the Ammergau Alps and the Tannheim Mountains.

Burg Hopfen is considered the earliest stone castle in the Allgäu, and its simple ring wall has no towers or bastions. The cleared rubble revealed walls up to three metres high, and some wall breaks had to be filled in for structural reasons.