Fort van Lier, Military fort in Lier, Belgium

Fort van Lier is a brick fort built between 1877 and 1890 as part of the Stelling van Antwerpen, the defensive belt around Antwerp. It has a trapezoidal plan surrounded by a 40 to 50 m wide moat, covering about 7.5 hectares inside the moat and roughly 37 hectares including moat and glacis. In 1906 the main caponier was reinforced with unreinforced concrete and armoured cupolas were added for 15, 12 and 5.7 cm guns.

The fort was constructed as part of Belgium's defensive fortification system to protect the region strategically against invasion. Its design followed a broader national plan created during a period of heightened military tension in Europe.

The fort has belonged to the city of Lier since 1950. Since 1989 the shooting club Fort Lier, which also covers archery, fishing and radio amateurs, has been allowed to use the site. The fort is a protected monument.

The fort lies on the Fortweg in Lier and is only partly accessible; since 1989 a shooting club, archers, anglers and radio amateurs have used parts of it. Access is by arrangement rather than freely through the whole site. The water in the 40–50 m wide moat contains 391 μg/L lead and 114 μg/L cadmium, so keep to the paths and do not touch the water.

The fort's moat water contains 391 μg/L of lead ions and 114 μg/L of cadmium ions, far above the 15 and 5 μg/L limits for drinking water; these heavy metals accumulate in the fish. The fort has belonged to the city of Lier since 1950, and since 1989 the shooting club Fort Lier, which also covers archery, fishing and radio amateurs, has been allowed to use it.