The remains of the Castle can be visited
Alt-Schauenburg Castle (Ruin)

On the Chleiflüeli near Frenkendorf in the canton of Basel-Landschaft is the Alt-Schauenburg ruin. It is the younger of the two Schauenburg castles and is on a rocky outcrop, surrounded on three sides by steep cliffs.
History+
The settlement of Alt-Schauenburg began around 1275 to 1280 and was part of the expansion of the Schauenburg clearing zone. The castle's use ended in 1356 due to the Basel earthquake. The damage was deemed too extensive for repair, especially considering the nearby Neu-Schauenburg, which was instead restored.
Source: Wikipedia · Licence: CC BY-SA 4.0
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 47.4957, 7.6731