Borgarvirki is a volcanic plug and natural fortress located in northern Iceland. Situated on the Vatnsnes peninsula, it serves as a significant landmark. The site holds historical importance, as it was reportedly used as a defensive fortress in early Icelandic history, although evidence of extensive human use or fortification is limited.

From a geological perspective, Borgarvirki consists of basalt layers that have hardened into columns, giving it a distinctive and rugged appearance. This natural formation has been supplemented with walls made of the same columnar basalt, which reinforced its structure and enabled its use as a fortification.

The site offers panoramic views of the surrounding landscape, making it a strategic spot for overseeing the area. Today, Borgarvirki attracts visitors interested in geology and history.

You can find Borgarvirki along the unpaved and rather poor road no. 717. And while you’re here, you definitely shouldn’t miss the nearby Hvítserkur rock.