The long casemates are located on the south western corner of the Citadel and were designed to defend the ditch at the south western end of the tenaille. They were constructed in the early phase of the forts development, and likley completed by around 1810. The group consists of two pairs of two-storeyed casemates, situated to the north and south of what was originally a deeply sunken area serving as a light well. (location accurate to the nearest 1m based on available information).