Named coastal rock fort on Kyrkogårdsön, begun in 1916 and first manned in 1926. It had underground quarters and services for 270 normally and up to 500 at full readiness, a reported 4–6 m concrete roof, two 15.2 cm main guns, four 57 mm guns, searchlights and control of a 400 m mine line. No floor area, tunnel length, excavation volume or original construction cost is given; the reported SEK 35m is a 1990s restoration/public-access project.

portals: value: 1 | unit: observed main portal | scope: focal fort | note: The article describes one gated entrance cut into the vertical rock face; total access/escape count is not established. | inner_structure: value: rock-cut corridors, quarters, clinic, kitchen, toilets, power/mining rooms and surface trenches/emplacements under mass concrete and rock | scope: focal fort | note: Plan dimensions and levels are absent. | other: range: 4; 6 | unit: m | scope: concrete roof thickness | note: Reported protective roof over the fort crown.; value: 270 | unit: persons | scope: normal garrison | note: Maximum reported readiness occupancy was 500.; value: 6 | unit: guns | scope: built fort armament | note: Two 15.2 cm main guns and four 57 mm guns; proposed southern expansion and torpedo battery were not built.; value: 400 | unit: m | scope: controlled mine line | note: 36 mines with provision for 10 additional mines.

amount: SEK 35,000,000 | year: 1994 onward | basis: restoration and conservation project | scope: Heritage restoration and public access; not original fort construction cost.

Quarters, clinic, kitchen, water closets and dry latrines; On-site generator for essential power; Speaking-tube communications; Two 15.2 cm guns, four 57 mm guns and protected ammunition/operations spaces; 5 kW 150 cm searchlight and smaller mobile searchlight; Control of a 36-mine, 400 m barrier with provision for 10 more mines; Open crown trenches, observation cupolas and shoreline obstacles

Unknown gallery/cavern excavation; Very thick mass-concrete roof; Gun emplacements, observation positions and mine-control interfaces; Habitability and power for a 270–500 person garrison; Island marine logistics; Heritage conservation versus military functional-equivalent standard

One fort within Vaxholm's outer defence line. Other forts/batteries described in the article, and the unbuilt southern extension and torpedo battery, are contextual and must not be priced into the focal unit.

Revised upward after source-specific review.

Measured floor plan and level count; Tunnel lengths and sections; Excavated volume; Concrete roof footprint and quantity; Portal/escape count; Gun-emplacement geometry; Geology, drainage and moisture-remediation scope; Original construction cost; Functional-equivalent versus heritage brief

Historic name can cause incorrect placement on Siarö rather than Kyrkogårdsön.; The current model's four mission packages do not correspond transparently to the source's two main and four secondary guns plus mine-control system.; The 4,000 m² / 43,056 ft² reference scale is a proxy inferred from occupancy, not a source-reported area.; The southern fort extension and three-torpedo battery were planned but never built and must remain excluded.; Severe humidity made the original underground accommodation unsuitable in peacetime; restoration/condition scope is material.