It is located near the town of Hobro, some distance from the present end of the Mariager Fjord in Northern Jutland.

Likely built during the reign of Harald Gormsson or his son Sweyn Forkbeard, the fortress may have served as barracks or as a defensive stronghold.

It would have help to enable control of the traffic on the main land-based trading route between Aalborg and Aarhus.

Because of its unique architecture and testimony to the strategic power of the House of Knýtlinga (Jelling dynasty), Fyrkat was inscribed on the UNESCO World Heritage List along with four other Viking ring castles in 2023.

In each of the four quarters stood four longhouses of the same design arranged in a square with a smaller house in the middle.

The innermost row was the lowest and the gaps filled horizontal with planks forming a wall to the inside of the fort.

The earth fill sloped to the inside so the ramparts could be easily accessed from every point of the circle road.

Along the outside ran a row of posts slanted to the wall either to support it at the top like buttresses or maybe in some sort of cruck like construction being the rafters of the roof.

Inside the houses, each end was walled off to make a small room, maybe a pantry or storeroom.

On the inside the great room had a large hearth in the middle and a raised wide bank alongside the outer walls for sleeping.

Carts have been found in many graves and it is speculated that it was meant to transport the body in the afterlife and that it was a symbol of status.

The ramparts, that had almost been ploughed level through the ages were piled up again and the postholes of the roads and buildings were filled with concrete.

With a total of about 30 graves of men, women and children some were buried in wagon crates such as were found in Oseberg, others in coffins.

In 1993 the visitor centre of Viking Center Fyrkat was built about one kilometre from the ring fort.

The center has an educational focus and aims at presenting a complete Viking Age environment here on the model of a supplier for the fort.

No Viking farm has been found near the ring fort of Fyrkat, the buildings have been reconstructed after excavated examples in Vorbasse, a small town in southern Jutland.