Linz Castle occupies the hill immediately above the Hauptplatz, a commanding position that has been fortified since Roman times. The current building is largely 16th to 17th century, a substantial complex of wings around a central courtyard. It now houses the collections of the Oberösterreichisches Landesmuseum (Upper Austrian State Museum), which covers natural history, archaeology, and art history.
The rooms devoted to medieval and early modern art and craft are the strongest part of the collection. There is also significant archaeological material from the Roman town of Lentia that underlies much of modern Linz. The real attraction for many visitors, though, is the terrace off the south wing, which offers a broad panoramic view over the Hauptplatz, the Danube, and the hills beyond. The view from up here makes clear why the Romans built here first.