Ehrenburg, Medieval castle in Plaue, Germany.

Ehrenburg is a castle complex in Plaue positioned on a hilltop overlooking the Thuringian countryside, featuring a central defensive tower and fortified walls. The structure displays typical elements of medieval military architecture with its protective design.

The castle was founded in 1324 under the Counts of Schwarzburg family and became an important center of power in the region. Over the centuries it suffered damage and was rebuilt several times before reaching its present form.

Locals still call the castle "Ernborg", a form recorded in old charters alongside Ernberg and Ernburg. Its origin is debated: some trace it to the old German word Oern for maple, others to the river Gera, called Ger in old German, which would give Gerburg. A prehistoric owner named Erin or Ero has also been suggested.

The castle is privately owned and not open to the public; since 2008 the owners have reopened the surroundings, and Plaue residents may enter the grounds by arrangement with the owners or, in their absence, the local caretakers. Access follows an old right of way through the site.

The castle is privately owned and not open to the public; since 2008 a German-British couple has reopened the grounds and begun reversing building mistakes from the first rebuild. Plaue residents may enter by arrangement with the owners or, in their absence, the local caretakers, citing an old right of way.