Schloss Schwarzau, Protected castle in Schwarzau am Steinfeld, Austria.

Schloss Schwarzau is a castle in Schwarzau am Steinfeld featuring a two-story main building with a striking gable. The structure sits on expansive grounds in Lower Austria and reflects construction styles from different periods.

Count Wilhelm von Wurmbrand-Stuppach initiated construction in 1567, while the current Baroque form developed beginning in 1697. This major rebuilding shaped the building's appearance for centuries to come.

The castle chapel hosted the 1911 wedding of Archduke Karl of Austria and Princess Zita of Bourbon-Parma. For the occasion the salons were renovated and the chapel benches replaced by chairs to seat more guests. A post office was set up in the park for gifts and congratulatory telegrams, and Pope Pius X sent a copy of Leonardo da Vinci's Last Supper in a gold frame. Karl's 2004 beatification set his memorial day on his wedding date.

The site has been a women's prison since December 1957, now the Justizanstalt Schwarzau, and is closed to visitors. The grounds belong to the Republic of Austria, not to a private owner, so access is controlled by the prison administration. Views of the former Baroque schloss are limited to its exterior from public roads in Schwarzau am Steinfeld.

Soviet forces occupied the building after World War II before the Austrian Republic purchased it in 1951. This military interlude is often overlooked in the property's more recent history.