Burgruine Schloßthal, Medieval castle ruins in Blankenheim, Germany.

Burgruine Schloßthal is a castle ruin site in Blankenheim in the Eifel region. Stone walls, a tower, and sections of the outer fortifications remain from its original medieval structure.

The Dollendorf lords, first mentioned in 893, lived at the castle until the mid-15th century. The castle itself was first documented in 1077. In the 12th century it became a Cologne fief, and in the 13th century it came under the feudal lordship of the counts of Luxembourg and Jülich.

Locals call the ruin "Finger Gottes" because its silhouette is visible from afar. Residents of Schloßthal traditionally celebrate New Year on the castle grounds, and the site also serves as a fire pit. An information board explains the history and architecture of the former hilltop castle.

The ruin stands in the Lampertstal nature reserve near Schloßthal, above the Ahr; remains of Burg Neuweiler lie about 380 m southeast and some 70 m lower, right beside the river. An information board covers the site's history and architecture. The grounds are used as a fire pit, and locals traditionally celebrate New Year there.

From the ruins, visitors look out across wide landscapes toward distant peaks like Nürburg and Hohe Acht. This long view was strategically important for defending the site.