Stack Rock Fort Travel Guide

Stack Rock Fort’s story begins centuries before its construction, with initial proposals dating back to 1539 by Thomas Cromwell, who envisioned fortifying the rocky island to guard Milford Haven Waterway. Despite early surveys in 1748 and 1817 recommending defenses, it was not until the mid-19th century, amid rising tensions with France under Napoleon III, that the British government acted. The fort was constructed between 1850 and 1852 to protect the Royal Dockyard at Pembroke Dock, a vital naval asset, from potential seaborne attacks.

The original structure was a three-gun elliptical tower, about 55 feet in diameter and 30 feet tall, housing three 32-pounder guns and a 12-pounder for dock wall defense. However, the arrival of ironclad warships rendered the initial design obsolete, prompting a major expansion from 1859 to 1871. This included encasing the original tower within a larger circular fort featuring casemates for 16 large rifled muzzle loader guns and accommodation for up to 175 troops and five officers. The fort’s walls were thickened to nearly 4.5 meters to withstand modern artillery, and plans for rooftop gun turrets were made though never realized.

Stack Rock Fort never saw combat but played a key defensive role, especially during World War I, when it monitored Milford Haven with two quick-firing 12-pounder guns and controlled anti-ship mines in the harbor. Its strategic importance diminished in the early 20th century, leading to disarmament in 1929. The fort was sold in 1932 and has since remained largely abandoned, its rusting cannons and weathered stone walls standing as silent witnesses to a bygone era of coastal defense.

The fort is privately owned and fully secured, with access restricted and visits requiring prior permission. Recently sold again, plans have emerged to preserve Stack Rock Fort as a 'living ruin' accessible to the community. Its isolated island setting, rugged maritime environment, and evocative military architecture make it a unique heritage site with potential for cultural and educational use, though it remains rough around the edges and off-grid.

Situated on a small rocky island about 800 yards offshore, Stack Rock Fort commands panoramic views over the Milford Haven Waterway and the Irish Sea beyond. The surrounding Pembrokeshire coast is renowned for its dramatic cliffs, natural arches, and rich wildlife, including seabird colonies that now inhabit the fort. Nearby coastal walks offer stunning vistas and connect to other historic sites, embedding the fort within a broader landscape of natural beauty and historical intrigue.

Stack Rock Fort exemplifies Victorian military engineering adapted to evolving naval technology. Its layered construction—from the original mid-19th-century gun tower to the expansive granite and limestone casemates—reflects the shifting demands of coastal defense. Though never tested in battle, the fort’s imposing presence and innovative design underscore the strategic foresight of its builders and the maritime heritage of West Wales.