Fort Knox, named after Major General Henry Knox, America's first Secretary of War and Commander of Artillery in the American Revolution, was begun in 1844 in response to fear of a British incursion across the Maine / New Brunswick border, and to defend the Penobscot River, which lead directly to Bangor, the capital of Maine’s rich lumber industry. The fort consists of a main building, and four outlying batteries. Constructed of cut granite, the fort has strong relationship to those of the same period in Fortress Halifax.
Though Fort Knox was staffed with soldiers during both the Civil War, and the Spanish-American wars, the fort never actually saw action, and never fired a shot in anger.
Though never fully completed (construction stopped in 1869), the main fort was designed to house 64 rifled-muzzle loading guns, with another 69 cannons to cover the lines of defence outside the main building. The largest gun installed at Fort Knox was a 15" Rodman. Rodman cannons were actually developed while the fort was still under construction, and required that the "A" and "B" batteries be modified to accommodate these "state of the art" cannons in 1865. The 15” Rodman needed about seven people operate it, and fired a shell weighing 315 pounds at a range up to 4,680 yards. This contrasts to Fort George (the Citadel), one of Britain's most powerful colonial defences, which had a total of 70 guns in 1855, the largest of which was an 8" gun.
Fort Knox was the first granite fort built in Maine, and would serve as the model for Fort Popham, Fort Gorges, Fort Preble and Fort Scammell in Maine. It was also the model for Fort Taber in Massachusetts. The forts, state of the art when conceived, could handle the new armaments of the second half of the 19th century, and their large granite casemates protecting the gun emplacements, were thought to offer stronger defences than the outdated wooden blockhouses of the earlier decades.
Fort Knox is cared for in part by the Friends of Fort Knox.