4.7
(80)
319
hikers
Ancient Fort Loop
01:48
6.65km
90m
Hiking
Hike the 4.1-mile Fornborgsrundan in Tyresta National Park, an easy route featuring ancient forests, lake views, and a prehistoric fortress.
Last updated: February 26, 2026
Tips
Your route passes through protected areas
Please check local regulations for:
Tyresta nationalpark
Waypoints
Start point
Parking
Get Directions
2.74 km
View of Lake Stensjön
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Tip by
3.27 km
View of the islands at Stensjöborg
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Tip by
4.05 km
View of lake in Tyresta National Park
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Tip by
6.65 km
End point
Parking
Way Types & Surfaces
Way Types
5.08 km
1.23 km
272 m
< 100 m
Surfaces
4.16 km
1.23 km
931 m
321 m
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Elevation
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Weather
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Sunday 10 May
16°C
4°C
63 %
Additional weather tips
Max wind speed: 5.0 km/h
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This route was planned by komoot.
Frequently Asked Questions
How challenging is the Fornborgsrundan trail?
While Komoot rates it as 'easy', the official park description categorizes the Fornborgsrundan as a 'fairly demanding hike' due to its hilly terrain and several steep slopes. Some even consider it one of the most difficult trails within Tyresta National Park. You should be prepared for rocky sections and an elevation gain of approximately 86 meters.
What kind of landscapes will I experience on the route?
The trail offers varied landscapes, including hilly terrain, rocky sections, and ancient old-growth forest with towering pine and spruce trees. A significant portion passes through an area affected by a 1999 forest fire, showcasing unique regeneration with blackened trees and new growth. You'll also enjoy picturesque views of lakes like Stensjön and Lanan.
Are there any notable viewpoints or landmarks along the way?
Yes, the trail's namesake, the Fornborg (a prehistoric fortress), offers a magnificent view over Lake Stensjön. You'll also find other scenic spots like the View of Lake Stensjön and the View of the islands at Stensjöborg. The unique forest fire area is also a distinctive feature.
Where can I park and access the trailhead?
The Fornborgsrundan trail is commonly accessed from the Stensjödal tenting area, which serves as a convenient starting point for the loop. Parking information for Tyresta National Park can typically be found on the official park website.
Is the Fornborgsrundan trail dog-friendly?
Tyresta National Park generally welcomes dogs, but they must be kept on a leash at all times to protect wildlife and ensure a pleasant experience for all visitors. Always check the latest park regulations before your visit.
What is the best time of year to hike this trail?
The trail can be enjoyed year-round, but each season offers a different experience. Late summer (August and September) is ideal for finding blueberries. Spring and autumn provide beautiful foliage and cooler temperatures. Winter hiking is possible but requires appropriate gear for snow and ice.
Do I need a permit or pay an entrance fee for Tyresta National Park?
No, there is no entrance fee to visit Tyresta National Park, and permits are generally not required for day hikes on established trails like the Fornborgsrundan. However, specific regulations apply for activities like camping or lighting fires, so it's always good to check the official park website for the latest information.
Are there any facilities or amenities available on the trail?
Yes, you'll find designated fire and resting places at Lake Lanan and Lake Stensjön. Fresh water and outdoor toilets are available at the Stensjödal tenting area, which is a common starting point for the loop.
What kind of wildlife might I encounter?
Tyresta National Park is home to diverse wildlife. You might spot various bird species, including the black woodpecker, and there's a chance to see moose among the trees, especially in quieter hours.
Does the Fornborgsrundan intersect with other well-known paths?
Yes, the route also passes through sections of the Sjöleden, Storskogsrundan, and Tyrestarundan trails, offering opportunities to explore more of Tyresta National Park.
How long does it typically take to complete the Fornborgsrundan?
The Fornborgsrundan is approximately 6.65 kilometers long. Komoot estimates a completion time of around 1 hour and 48 minutes, but this can vary depending on your pace and how often you stop to enjoy the scenery.
Nearby routes
Trail Reviews
25 kilometers south of Stockholm. What's 6.5 kilometers? This hike looks easy, but it's almost entirely over natural rock and natural forest floor with rocks and roots, with gentle ups and downs. Steep sections have steps, and boggy passages are covered with planks. Surefootedness is required; you won't make fast progress. The hike is definitely not "easy," but rather "moderate"! In any case, it's a beautiful hike with a charming lake in the nature park, where a rejuvenated forest 🌳 has emerged after a fire 25 years ago. Sporty types will manage the loop with flying colors, but inexperienced everyday hikers should take their time and enjoy the trail.
Last night, around five o'clock, we moved to my third and final gateway to Tyresta NP, Stensjödal. It was deserted and quiet. After a short night, engrossed in the pages of my 📖 for too long, I woke up at a quarter past eight. The forest 🌳 was shrouded in silence, no visitors in sight. After breakfast, we put on our pink Altras to walk the black trail, to add a little color to the scene🤣. At Nedre Dammen Lake, I discovered Stensjödal, the half-timbered farmhouse once called the miller's cottage. Built in the 18th century, restored in the 19th, when the water here still pulsed with the rhythm of labor. The mill, the sawmill, the forge—everything was powered by the Åvaån River. Farmers brought their grain, had it milled into flour, a cycle of land and water that fed the village. In the mid-19th century: twelve farms, more than a hundred barrels of grain per year. I can almost hear it: the rattling of wheels, the flowing of the water, the voice of the miller who lived here, close to his work. It's a walk over rocks and roots, along glittering water and trees that create new landscapes in their fall. Some paths seem very familiar, as if I walked them just two days ago, but then under a completely different star. 😥 As we approach the camper again, the first people cross our path. With baskets yet to be filled, with backpacks 🎒 for a weekend trip, parents taking children by the hand, ready for their own adventure. The cars are already crowded around the camper. Time to make way and set off on our next discovery.