Fort Southwick

Fort Southwick is a fortified structure on the highest point of Portsdown Hill with reinforced walls, deep ditches, and a crescent-shaped barracks building. It contains an underground network of tunnels and passages that connect different sections of the fort and allowed movement between defensive positions.

Built between 1861 and 1870 under Prime Minister Palmerston's direction, the fort was designed to protect Portsmouth's naval base from land-based attacks. It was constructed during a period when Britain was building new defensive works along its coast.

This Victorian fort shows how military engineers designed defensive structures in the 1800s through tunnels, caponiers, and angled walls. The layout reflects the thinking of that era about protecting important locations and preparing soldiers for different situations.

The site functions today as a business park and requires ongoing maintenance to preserve its stone structures from deterioration. Access may be limited in some areas since portions are in private use.

During World War II, the fort contained an underground headquarters with four main tunnels that served as a communications center for Operation Overlord. This hidden command center played an important role in coordinating invasion plans.

Location: City of Portsmouth

Location: Southwick and Widley

Inception: 1861

GPS coordinates: 50.85830,-1.10871

Latest update: December 10, 2025 16:26