Ancient Monuments

History on the Ground

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Stack Rock Fort

A Scheduled Monument in Angle, Pembrokeshire (Sir Benfro)

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Latitude: 51.7025 / 51°42'9"N

Longitude: -5.0921 / 5°5'31"W

OS Eastings: 186434

OS Northings: 204946

OS Grid: SM864049

Mapcode National: GBR G4.YW6R

Mapcode Global: VH1RX.PGCP

Entry Name: Stack Rock Fort

Scheduled Date: 28 January 1959

Source: Cadw

Source ID: 2061

Cadw Legacy ID: PE334

Schedule Class: Defence

Category: Fort

Period: Post Medieval/Modern

County: Pembrokeshire (Sir Benfro)

Community: Angle

Traditional County: Pembrokeshire


The monument comprises a masonry fort built in in several phases during 1852-1871 to defend the middle part of Milford Haven and the Royal Naval Dockyard at Pembroke Dock against the threat of French invasion under Napoleon III. Located on a rock islet in mid-channel the first building dates to 1850-2 and is a two storey limestone gun tower, trefoil in plan with an open air flat roof that held three guns. Following a change from smooth-bore to rifled guns and the development of ironclad ships in 1858 the fort was rebuilt between 1859 and 1864. The original tower was encased by a ring of rock-faced limestone and granite gun casemates built from granite piers with iron shields in-between to occupy three-quarters of a circle, the remainder holding a recessed two-storey accommodation block on the north side providing for 4 officers and 152 men with additional guns in casemates. The final armament was 16 ten-inch guns in the casemates and 7 seven- inch guns protecting the north block. By 1874 the ten-inch guns were obsolete as the size of the casemate shield ports prevented the installation of larger guns and this armament then remained in position until dismantled in 1922, the fort having been abandoned after 1918. The building is also Grade II* listed.

The monument is of national importance for its potential to enhance our knowledge of 20th century military organisation. The monument forms an important element within the wider context of the military history of Wales and the structures may contain well preserved archaeological evidence concerning chronology, layout and building techniques.

The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive.

Source: Cadw

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