The Beilstein is a 499.5 m above sea level. NHN high mountain in the Spessart. It lies to the east of the road from Bad Orb into the Jossatal between Villbach and Lettgenbrunn in the municipality of Jossgrund in the Main-Kinzig district of Hesse.
The Beilstein is a basalt cone with the largest basalt cave in the Main-Kinzig district. The formation was formed by volcanic eruptions 10 to 20 million years ago; the surrounding red sandstone, which otherwise characterizes the Spessart, is around 200 million years older. The basalt breach was exposed by erosion; The typical basalt columns and smaller, spherical structures can be seen on the rock walls.
On the mountain, which was first mentioned in a document in 1059, are the remains of the small, medieval hilltop castle of Beilstein. It was built to protect the possessions of the archbishopric of Mainz and to control an old road, and was first mentioned in 1343. It was also intended to protect the first glassworks that were established. When rule passed to the Counts of Hanau, the castle probably lost its importance and has since fallen into disrepair. Due to the poor source situation, little is known about the castle. Today the complex consists only of a ring of walls about 12 meters long.
Source: Wikipedia