Tunaborgen

The remnants of Tunaborgen include a square tower, a bastion, and courtyard walls positioned near the entrance of an ancient waterway.

The fortress, first documented in 1291 by Archbishop Nils Alleson, functioned as a strategic defense point along the maritime route to Uppsala.

The excavated ground floor reveals three brick-encased windows and supports for four ribbed vaults, exemplifying medieval Swedish architectural methods.

The ruins, protected by a wooden roof and secured by gates, require prior arrangements with local authorities for interior access.

Ground radar surveys in 2014 detected additional walls beneath the surrounding grasslands, suggesting a larger medieval complex than initially understood.

Location: Österåker Municipality

GPS coordinates: 59.46903,18.29791

Latest update: March 29, 2025 16:23