Viking Ring Fortress Nonnebakken

Viking Ring Fortress Nonnebakken in Odense is part of the network of circular fortresses linked to King Harald Bluetooth around the year 980. Together with sites such as Aggersborg, Fyrkat, Trelleborg, Borgring and probably Borgeby in Skåne, it formed a strategic system for controlling the kingdom and meeting threats from outside. Today the original ring fortress has been levelled, but the castle mound survives, now occupied by the Odd Fellow Lodge. Some traces remain visible in the terrain, while other well‑preserved sections lie concealed beneath the modern city streets and buildings.

Stop at Nonnebakken to connect the modern city of Odense with its Viking past. On site you can identify the smoothed castle mound and sense the scale of the circular fortress, even though much of it is hidden underground. It works well as a short, thoughtful detour while exploring the nearby city centre.

A brief but meaningful stop to visualise a Viking ring fortress embedded in modern Odense.

Planning your visit

How long to stay

30-45 minutes

Best time to visit

Daytime, when remaining earthworks and the surrounding cityscape are easiest to interpret and combine with other nearby stops in Odense.

Around here

Nearby on the Margueritruten

• Balance Arc - sculpture

  Attraction · 100 m

• Gallery 5000 - private gallery

  Art gallery · 184 m

• Odense Prison - historical building

  Attraction · 245 m

• Byfisk på muren (Fish in the city)

  Attraction · 267 m

• The Butterflies in the lake

  Attraction · 280 m

• Munke Mose Park

  Park · 299 m

Frequently asked

What is Viking Ring Fortress Nonnebakken in Odense?

Viking Ring Fortress Nonnebakken is the site of a circular fortress associated with King Harald Bluetooth’s defensive and administrative system from around 980. It was one of several ring castles across what is now Denmark and southern Scandinavia, intended both to control the interior of the kingdom and to face potential enemies from outside. Today only the levelled mound and subtle traces remain visible.

Can I still see the Viking ring fortress at Nonnebakken today?

You can no longer see a complete fortress, but the castle mound survives and is now occupied by the Odd Fellow Lodge. The shape of the terrain hints at the former ramparts. Other parts of the structure are reported to be well preserved below ground, but these sections are hidden beneath modern buildings and streets and are not visible as standing remains.

How long should I plan to spend at Nonnebakken?

Nonnebakken works best as a short stop rather than a half‑day visit. Many visitors will be able to walk around the mound, read any available information on site, and form a sense of the former ring fortress in well under an hour. It is easy to combine with other nearby sights in Odense’s central area.

Is Viking Ring Fortress Nonnebakken easy to visit from the Margueritruten scenic route?

Nonnebakken lies a short distance from the Margueritruten, within Odense’s built‑up area. Drivers can leave the route briefly, approach the city centre, and then continue their journey after a quick visit. Because the site is integrated into the modern cityscape, it is suitable for a brief detour rather than a long countryside walk.

How does Nonnebakken relate to other Viking ring fortresses in Denmark?

Nonnebakken was one of at least five known Viking ring castles connected with King Harald Bluetooth’s rule, alongside Aggersborg at the Limfjord, Fyrkat at Hobro, Trelleborg at Slagelse, Borgring at Køge and probably Borgeby in Skåne. Together they formed a coordinated system for unifying and defending the early Danish kingdom.

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