South Hook Fort, on the northern shore of Milford Haven, Pembrokeshire, is a Grade II* listed building which belongs to a series of forts built as part of the inner line of defence of the Haven following the Royal Commission on the Defence of the United Kingdom.

It comprises two separate batteries protected by earthworks and connected to the fort by covered walkways.

Its complement included a Defence Electric Light searchlight unit manned by 200 men, and its guns were aligned to provide crossfire with those at Hubberston and Popton across the Haven.

[3] The fort was part of the Palmerston fortifications meant to defend the harbour of Milford Haven.

The fort later became part of the double defences of the Haven and was built to a similar design as that at Hubberstone.