Tags: Military Structure.
Olsborg Castle (Swedish: Olsborg) also Olofsborg was as a fortified castle located in Tanum Municipality Sweden in the province of Bohuslän. It is located on a steep cliff and might previous to later use been an early hill fort. It was constructed in 1503 or 1504 by the squire Nils Ragvaldsson from Åby after a recent Swedish attack on Viken.