Hasegg Castle was completed in the 13th century. At the time, it was a strategic location to provide effective protection for the salt works, i.e. the place where salt was produced. It was also used to keep a close watch on the old salt route and river navigation (the Inn was very busy).
The castle takes its name from the term "Pfannhauseck", which means "corner of the stove building". Originally, Hasegg was located at the corner of a salt-making building used to heat the brine.