Fredriksborg Fortress, Coastal fortress in Värmdö, Sweden

Fredriksborg Fortress consists of a four-storey masonry tower on a plateau about 40 metres above the water, surrounded by a moat and reached by a drawbridge whose original machinery survives. Below it, the shore battery was a caponier with a three-storey north wing and a two-storey south wing; only the north caponier remains. A stone barracks designed by Carl Hårleman stands just above the battery.

The fortress was built in 1735 under King Frederik I and served as a military installation to protect the waters off the Stockholm coast. It played an important role in Swedish defensive strategy against potential attackers from the sea.

The fortress is named after King Fredrik I, in whose reign it was completed in 1735. The preserved stone barracks, built to Carl Hårleman's drawings just above the shore battery in the late 1750s, now houses the Fredriksborg hotel and restaurant, which offers guided tours of the fortress from May to September.

Guided tours of the fortress run from May to September. The stone barracks, now a hotel and restaurant, occupies the site above the shore battery. The drawbridge machinery is preserved in its original state.

From the higher tower, visitors can see across the archipelago to Stockholm's central districts on clear days. This far-reaching line of sight was strategically important in the 18th century for both defense and communication.