Ancient castles in Sweden - 18 Swedish ancient castles

Ancient castles in Sweden! Think it's boring to look at an "old gravel pile" on top of a mountain? Actually, it is staggering that parts of these historic structures still exist. Once upon a time our ancestors used them, as a refuge in times of trouble, for defence or perhaps as a guard post.

Ancient castles in Sweden

Swedish ancient castles are fortified structures from ancient or early medieval times. When we talk about antiquity in the Nordic region, we mean the time from the arrival of humans in our part of the world until the 11th century AD. Here are 18 ancient castles that all have fantastic stories to tell.

1. Rödklitten on the High Coast

On a hill in Kramfors municipality in Ångermanland is the ancient castle Rödklitten. It is one of nine ancient castles in Västernorrland County and is thought to date from the Late Iron Age, around 400-1050 AD.

The castle, which today consists of a collapsed stone wall, is about 40 metres long and two to five metres wide. It can be reached by hiking along the World Heritage Trail, and the views from the top are said to be spectacular.

2. Stensättersborgen on the High Coast

Borgberget rises 190 metres above sea level and slopes steeply on all sides, except to the southeast. This direction was once blocked by a 135 metre long stone wall, up to four metres wide and 2.5 metres high. Below this wall, another wall was built.

Stensättersborgen on Borgberget is the highest and most well-preserved of all known ancient castles in Norrland. The castle is located near the village of Stensätter in High coast, in the municipality of Kramfors.

3. Broborg in Uppland

In Knivsta, north of Stockholm, you will find Uppland's largest ancient castle, Broborg from the early Iron Age. Here you can still see the double walls clearly as well as traces of so-called vitrification, a way of building that involved heating the stone so that it was vitrified and became extra strong.

The site has information panels telling the legend of the female Viking chieftain Grimsa and her brother, who both fought for power. You will also be able to enjoy beautiful scenery and views.

4. Gottsunda ancient castle in Österåker.

Gottsundaborgen is one of the ancient monuments in Österåker municipality, in Stockholm County. The fortress is located on a ridge that drops steeply down towards Lake Storträsket. In the other directions, a long stone wall was built as protection.

It is not known for certain how the ancient castle was used, but it is possible that an important function was to guard the important sailing route Långhundraleden, which passed through here.

5. Birkaborgen on Björkö in Lake Mälaren.

Birkaborgen is the name of an ancient castle at Birka on Björkö outside Stockholm. The castle has been dated to the Viking Age and is one of the few surviving large buildings from this period. The castle was used until the 10th or 11th century, after which it was abandoned.

The castle wall is about 350 metres long, two to three metres high and seven to eight metres wide, with several entrances. Under the wall is a tomb dated to the 7th century, where a man and a horse were buried. Nearby was the so-called Garrison, consisting of a couple of houses, where exciting finds were made in the form of spearheads and parts of Viking Age armour.

6. The ancient castle of Gåseborg in Stockholm

I Görväln Nature Reserve outside Stockholm are the ruins of the Gåseborg fortress, which has been dated to somewhere between 300 and 500 AD.

The castle is located at the top of a hill with a natural slope towards the sea. From the other side, the castle is surrounded by walls with two entrances.

Other reasons to visit Gåseborg in Görväln Nature Reserve are the beautiful nature and the fantastic views. Nearby you will also find Görväln Castle.

7. Halleberg in Vänersborg

Halleberg, which is located outside Vänersborgis considered the largest ancient castle in Scandinavia. The sheltered hilltop location has been used as a refuge for people from the time of the Migration Period, when the castle was built, until the Russian War of Gustav II in 1788.

The steep sides of the mountain made the castle almost naturally fortified. With the help of cobblestone walls, the site became virtually impregnable. Remains of the old walls can be seen today on the north side of the access road from Vargön in Storegårds klev. There are also other ancient monuments in the vicinity, such as the Hästevad stones and the legendary Häcklan dome.

8. Mösseberg's ancient castle in Falköping.

At Mösseberg outside Falköping is one of Sweden's largest ancient castles. The age of the castle is uncertain, but it may be from the Neolithic period. When it was built, people took advantage of the fact that its location on the hill, with a cliff at the edge, provided protection.

The building consists of a 770 metre long inner wall and a 420 metre long outer wall. The castle was probably used as a shelter in times of unrest. It may also have been used to guard an important road that passed below. Today, the mountain where this ancient Swedish castle is located offers a view that stretches for miles.

9. Gripeberg in Växjö

Gripeberg is an ancient fortress in the Notteryd nature reserve outside of Växjö. The site, which includes the remains of walls, is located on a hill and is surrounded by several steep cliffs. It is believed that the castle was mainly built in the Bronze Age, between 1630 and 410 BC. It was probably used for religious and cultural events.

In addition to visiting the archaeological site itself, you can hike and enjoy the nature in the nature reserve. From the hill you will also have a nice view of the area.

10. Torsburgen on Gotland

Torsburgen is an ancient castle located on a 71 metre high cliff on Gotland. At 1.2 square kilometres, it is the third largest in the Nordic region, after Halleberg in Vänersborg and Söholt/Hejrede Castle in Denmark.

Excavations show that the castle dates back to the time around the birth of Christ. It is believed to have been used to protect the population during times of unrest until the Viking Age.

11. Eketorp's ancient castle on Öland

Eketorp Castle protected settlements between the 3rd and 13th centuries. Today this is the only one of Öland's ancient castles which has been restored to its original appearance, and the castle is a major attraction.

A number of farmhouses have been built in the courtyard, so you can see what it might have looked like in the past. During the high season, you can also expect everything from small open museum houses to activities such as bread baking and archery.

12. Ismantorp fortress on Öland, Sweden

Ismantorp's castle is a circular castle with nine gates in a circular wall with a circumference of 400 metres. Inside the castle there are 95 house foundations, which are close together. The castle was built and used between about 300 and 600 AD, and its construction is thought to have been inspired by both Roman encampments and Norse mythology. 

Equipping a ring wall with as many as nine gates was hardly practical for defence purposes. It is therefore believed that the gates are related to the nine worlds of mythology, perhaps with the world tree Yggdrasil in the centre.

13. Gråborg on Öland

When Gråborg was built in the 3rd century, it was an impressive structure that could be seen from far away. Like Ismantorp Castle, the castle was equipped with nine openings in the wall, possibly to symbolise the nine worlds in Norse mythology. 

Roman gold coins (solidus) have been found in the castle, indicating both wealth and a time of travelling and contacts across the world. The castle is one of several restored in the 12th century, meaning it is better preserved than many others.

14. Sandby Castle on Öland

Sandby Castle is not much of an attraction at the moment, but its history is perhaps one of the most exciting. In 2010, a large amount of exclusive jewellery from the 4th century was found in the castle. When excavations began, a terrible story emerged.

Everywhere in the castle, the remains of people killed by force were found.The photos below were taken at an exhibition on the castle at the University of Copenhagen. Kalmar County Museum in Kalmar. There you can also read about different theories about what might have happened.

15. Bårby fornborg on Öland

Bårby Castle is located on the south-western part of the Ölandand was built between 400 and 700 AD. The settlement was carefully planned and the houses were built with common walls, almost like modern terraced houses.

Inside the castle, a farmer in the early 20th century found a gold coin from Eastern Europe. However, the only thing visible today is the circular rampart.

16. Havor fornborg on Gotland

Archaeological excavations around Havor show that the fortress was probably built around the time of Christ's birth. The castle consists of a circular mound, which in turn is surrounded by moats. Inside, there was once a two-metre wide wall. It is not clear how the castle was used, but it may have been used as a fortress or fortified farm.

At Havor, the so-called Havor Treasure has been found with a wine bucket, bronze bells and a large gold ring. Some of the artefacts can be seen today at the Gotland Museum.

17. Darsgärde ancient castle in Uppland.

The ancient castle at Darsgärde outside of Norrtälje was inhabited during the Migration Period. This was a turbulent time, and research shows that the castle was burned and rebuilt several times. Around 500 AD it was abandoned for good.

The castle is located on a hill and the remains of the old ramparts can still be seen today. Inside the castle, ruins of house foundations and other artefacts have been found that show that there was a farm that was inhabited all year round.

18. Trelleborgen Castle in Trelleborg.

I Trelleborg in the 9th century, there was a Viking castle or 'trelleborg', which in Danish is a ring castle. The remains of the castle were only discovered in the 1980s and the findings were sensational. The castle was the first "trelleborg" found in Skåne, and is today one of several found in Denmark in particular.

Trelleborg Castle was about 140 metres in diameter, connected to the sea by a navigable river and crossed by four roads. The castle was part of the kingdom ruled by the powerful Viking king Harald Bluetooth. Today, in addition to the castle, there is also a Viking museum, a recreated medieval house and a Viking farm with a period decorated longhouse. 

More unique ancient castles in Sweden

In addition to the Swedish ancient castles mentioned in the report, there are of course many more ancient castles in Sweden. Here you will find some more unique castles from the old days:

• Sörby village is a rediscovered ancient castle on Öland, the largest on the island.
• Walled hall is an ancient castle on Sirkön in Lake Åsnen in Småland.

Tips for even more Swedish ancient castles

Do you have tips for even more ancient castles in Sweden? Let us know!

Facts about Fornborgar in Sweden

• Definition: Fortified site from prehistoric or early medieval times.
• Number: There are more than 1200 registered ancient castles in Sweden, in the register of ancient monuments.
• Location: Most are high in mountainous terrain, bounded by natural cliffs and built walls. Some are located along important shipping routes and others are on flat terrain.
• Distribution in the country: Many Swedish ancient castles are located in Södermanland, Uppland, Östergötland, Bohuslän, Småland, Gotland and Öland.
• Function: Ancient forts in Sweden have been used for refuge in times of trouble, defence, guard posts or Roman-style camps.