Built in 1685, the Lambert Redoubt was part of a fort of the same name. It was a component of the median line of the plain front.
The redoubt was renovated in 1835/36 and given a roof. Constructed in a pentagonal form, it contained two floors and was surrounded by a network of casemates which are still in excellent condition today. There was a scattering of new mine chambers. Demolition work between 1868 and 1874 razed the entire fort to the ground.
Recent excavations for the Monterey underground car park brought the remains of the Lambert Redoubt to light.