Château de Rothenbourg, Medieval castle ruins in Philippsbourg, France

Château de Rothenbourg is a castle ruin situated on a forested hilltop near Philippsbourg. The remains display sandstone walls and structural foundations from the early medieval period.

The castle was probably built in 906 by Otbert, the 37th Bishop of Strasbourg, who had quarrelled with his subjects and fled; he was murdered at the Rathburg, perhaps this site, around 912–913. In 1353 Count Walram of Zweibrücken-Bitsch gave half of Rothenburg as a fief to Gerhard Harnasch von Weisskirchen. In 1369 Strasbourg's burghers took and dismantled the castle, which was apparently never rebuilt.

The name Rothenburg means "red castle", after the reddish sandstone of the hill. The ruin is state property and is listed in the general inventory of cultural heritage, not as a historic monument. The site is linked to the Blick de Rothenburg family, which held fiefs from the Lords of Bitche and died out in 1749.

The ruin stands on the Rothenberg hill above the Rothenbach valley, roughly 3 km as the crow flies from Neunhoffen and north of the Falkenstein and Helfenstein castles. It is reached on foot through woodland; the masonry is moss-covered and the ground around the base is covered with dry leaves, so wear suitable footwear. The site is state property.

The castle probably gave its name to the Blick de Rothenburg family, who held several fiefs from the Lords of Bitche and died out in 1749. The ruin is the easternmost castle in the Moselle département and in the former Lorraine region.