The remains of the Castle can be visited
Ödenburg Castle (Ruin)

The Ödenburg ruin, also known by names such as Heltburg or Oltenburg, is a castle complex dating back to the 10th century. It is located halfway between Wenslingen and Tecknau in the Swiss canton of Basel-Landschaft on a rock spur.
History+
The origins of Ödenburg date back to the late 10th century. Although its original name has not been preserved, it is believed to have been founded by the Counts of Homberg. The use of the complex ended as early as the late 12th century, possibly around 1150, which explains the sparse written sources. In 1320, the ruin was owned by the House of Habsburg-Laufenburg, after the Homberg fief reverted to Habsburg-Laufenburg following their extinction in 1223.
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: 47.4418, 7.8945