Burgruine Ried is a castle ruin located at Riederberg in the Wienerwald near Tulln in Lower Austria, with origins dating to approximately 1200. First documented in 1125 under feudal lord Hadmar v. Kuenring, the castle changed hands multiple times during the medieval period, eventually becoming property of the influential Habsburg sphere. The fortress fell into disrepair during the 15th century. Today, sparse remains include a Romanesque round tower, curtain wall, and outer fortress structures. The round tower underwent professional restoration in 2010 in collaboration with federal monument authorities, and the site remains actively researched by a dedicated preservation association that conducts archaeological excavations and hosts public engagement events.