Fort Tourgis was sometimes called the Citadel and is one of the larger forts. Fort Tourgis was completed in 1855 and had a total of five batteries holding thirty three guns and four mortars. Each of these batteries had a magazine. The total armament was made up of eight 68-pdr SB guns, fifteen 8-inch shell guns, ten 32-pdr SB guns and four 13-inch Mortars.
Fort Tourgis has a barrack block for a garrison of 346 soldiers. Unusually, there is a Redan on the land side protecting the approaches from the East.