When you enter the Fort, you are standing in the Advanced Battery which is named for the grouping of guns at the point, in advance of the main Fort. The purposes of these guns were to protect the Fort from a potential attack from the lake, even though this attack was highly unlikely. The guns situated in the Advanced Battery are on the highest point in the Kingston area (about 100 feet above the water) and could easily outrange any hostile naval guns. Also, the Royal Navy's strong presence at the dockyard would likely discourage any naval attack. A more likely route of attack would come from the North, overland. As a result, the Fort's defences were oriented towards the impending threat.
The metal-roofed buildings on either side of the Advanced Battery were constructed later than the rest of the fort, from 1841 to 1843. In 1867, they were used as commissariat stores.