Burg Schwarzenfels, Medieval castle ruins in Sinntal, Germany

Burg Schwarzenfels is a medieval castle complex in Sinntal, Hesse, made up of a keep, residential buildings, and a Renaissance portal. The structures combine stone masonry and timber framing, with the keep being the oldest surviving part of the site.

The castle was built in 1280 and passed to the House of Hanau in 1333, who used it as an administrative center for the region. It suffered heavy damage during the Thirty Years' War and was never fully restored afterward.

The Renaissance portal from 1621 shows carved columns and a knight figure, giving visitors a clear sense of how the castle's owners wanted to present themselves. Decorative stonework like this was a common way to signal rank and connections during that period.

The keep, 25 metres high, was renovated in 2015/16 and now has a steel staircase inside and out plus a viewing platform of metal grating and glass. The castle is leased since 2007 to a association of Schwarzenfels citizens; a youth hostel has occupied the first floor of the 1557 Marstall building since 1979.

The name Schwarzenfels is said to come from the black dolerite used to build it. The 25-metre keep was extensively renovated in 2015/16, gaining a steel external and internal staircase and a new viewing platform of metal grating and glass. Since 2007 the monument has been leased to an association founded by Schwarzenfels citizens, who also run the youth hostel in the first floor of the 1557 Marstall building, in use there since 1979.