Alt-Geroldseck Castle, Medieval castle ruin in Seelbach, Germany

Alt-Geroldseck Castle, also called Rauhkasten, is a ruined spur castle on a 604-metre-high ridge 1,750 metres north of Hohengeroldseck, above the Schönberg district of Seelbach. The small 400-square-metre site preserves only a few wall remnants of the shield wall and the palas, plus the neck ditch cut across the ridge.

The Lords of Geroldseck built the castle in the 12th century; it was first documented in 1139. In 1277 it was abandoned in favour of Hohengeroldseck, after which it fell into ruin. Only remnants of the shield wall, the palas and the neck ditch survive of the 400-square-metre complex.

The name Rauhkasten, also used for the site, refers to the rough, box-like spur on which the ruin stands. The small 400-square-metre complex was abandoned in 1277 in favour of Hohengeroldseck, 1750 metres to the south, and its remains have been studied in the Ortenau historical journal Die Ortenau.

The ruin is accessible on foot through forested terrain and hilly ground, so sturdy footwear is recommended for the walk. The path is passable most of the year but can become slippery after rainfall.

The castle is also called Rauhkasten, and its whole walled area covered only about 400 square metres, making it one of the smallest castle sites of the Geroldseck family. Only fragments of the shield wall, the hall building and the neck ditch survive.