Reenduff Battery was initially called Lower West Battery. It was built at the same time as the nearby Derrycreeveen Battery with construction taking place between 1898 and 1903. A rock cutting was made through the ridge on the north side of the battery, giving access to the foreshore opposite Queenstown (Castletown-Bearhaven) where a pier was built. It is believed that the guns for both batteries were hauled in through this cutting for installation.
Reenduff Battery mounted two 4.7-inch Quick Fire guns and was built over the remains of an old Napoleonic redoubt. The original Napoleonic ramparts with walkway can still be seen in the gorge of the battery. The 4.7-inch magazines were off set to the south of the Battery, left of the B Gun. These magazines have now been backfilled. The underground works between the two gun pits was used for an engine room and crew shelters and have recently been used as cattle shelter. The fire command position can still bee seen between the two gun emplacements.
The entrance to the Battery is dominated by the guard house and caretakers residence which was defensible. To the rear of the Battery is a more modern engine room for the three search light emplacements that lie to the front of the battery.