Neu-Thierstein Castle

Burg Neu-Thierstein, also known as Schloss Thierstein, is the ruin of a medieval spur castle perched on a rocky promontory between Büsserach and Erschwil in the Swiss canton of Solothurn. Built around 1180, it served as the ancestral seat of the Counts of Thierstein, one of the most influential noble houses of the region, until the line died out in the early 15th century. Its commanding position on the cliff above the Lüsseltal gave it strategic importance during the medieval period and still defines the skyline of the Schwarzbubenland area today. Accessible via hiking trails from Büsserach, the surviving walls offer open views across the valley — a quiet, off-the-beaten-track site listed as a Swiss cultural heritage monument of regional significance.