Fort Hubberstone is located on the north shore of Milford Haven opposite to Fort Popton on the south shore.
The Fort was approved by the Royal Commission of 1860 as one of the ‘Palmerston Forts’. It was built between 1860 and 1863 to mount eleven 9-inch RML gun in a Casemated Battery with iron shields. This battery was on the shoreline, with the barrack building about 100 metres to the rear.
By 1885 three 7-inch RML guns in Moncrieff Pitts had been built on the casemated containing the original nine 9-inch RML guns. Three 10-inch RML guns were later added in an open battery.
By 1900 the Fort had become largely redundant apart from a 12-pdr QF gun.
The Barrack Block was defended by a dry ditch with one caponier and two counterscarp galleries. The whole complex was surrounded by a defensible wall.