The Roman fort at Weissenburg (German: Kastell Weißenburg), called Biriciana in ancient times, is a former Roman ala castellum, which is a UNESCO World Heritage Site located near the Upper Germanic-Rhaetian Limes.

It lies in the borough of Weißenburg in the Middle Franconian county of Weißenburg-Gunzenhausen in Germany.

Today the castellum is one of the most important sites of research in the Roman limes in Germany.

The site contains partly subterranean building remains, a reconstructed north gateway, large thermal baths and a Roman Museum with an integrated Limes Information Centre.