Scharfenberg Castle, Rock castle in Annweiler, Germany.

Scharfenberg Castle is a ruined medieval rock castle on the 485-metre Scharfenberg, a rounded rocky hill in the Wasgau above Annweiler. Its landmark is a 20-metre bergfried clad in rusticated ashlars from the Hohenstaufen era. Parts of the well tower and the enceinte survive in the lower ward.

Scharfenberg Castle was built in the first half of the 12th century under the Hohenstaufen king Conrad III, who died in 1152. It probably served initially as a state prison. In the early 13th century it became the seat of Conrad III of Scharfenberg, Bishop of Speyer and Chancellor of the Empire. It has been a ruin since its destruction in the Peasants' War of 1525.

Scharfenberg sits in a forested area near Annweiler and belongs to a group of three castles that can be visited together on foot. Walking the path between them gives a clear sense of how these fortifications were placed in relation to one another.

The ruin is reached by foot along hiking trails that also connect to the nearby castles of Trifels and Anebos. The paths can be steep and rocky in places, so sturdy footwear is a good idea before heading out.

While Trifels is known as the place where imperial treasures were kept, Scharfenberg served at times as a state prison, a detail that sets it apart from the other castles nearby. Both were built around the same period yet were given very different roles within the same defensive system.