Historic California Posts, Camps, Stations and Airfields
The Citadel of Alcatraz
by Gordon Chappell
Regional Historian, Pacific West Region
National Park Service
The Post of Alcatraz in 1908, just before the Citadel was razed. The Citadel is the building on the top of the island. (Photograph courtesy of the National Archives)
Alcatraz Island in San Francisco Bay is famous as a United States Penitentiary for a period of roughly thirty years--1933 to 1963. Yet it was an army post for eighty years, first a heavy artillery coast defense installation guarding the strait into San Francisco Bay, then as its defense importance waned, increasing in importance as a military prison. In fact it was the Army, not the Department of Justice, that built the prison buildings later so famous as the home of Al "Scarface" Capone and other notorious criminals.
Frequently described as "America's Devil's Island" while a prison, Alcatraz was equally unique as "America's Gibraltar," a nearly impregnable fortress in its early days. Furthermore, as a fortification Alcatraz was unique in its design. There were forts in the harbors of Boston, New York, Charleston, Pensacola, and elsewhere in America, but none even remotely approached Alcatraz in the form of the fortifications, its strategic location in the harbor it protected, or in its topography. Most such forts were on low-lying islands, not high above the water. But Alcatraz, a steep, rocky mass reaching high above the bay, was unique as a platform for fortifications.
The key element in the fortifications of what the Army spelled variously as Alcatrazes, Alcatras, Alcatrasas, Alcatrace, Alcatrose, Alcatrazas, Alcatrazos, Alcatrases, and Alcatraz, and termed officially the "Post of Alcatraz Island" and, on rare occasions, "Fort Alcatraz" was a number of barbette batteries constructed in the rock with brick and stone breast height walls, located mostly around the southwestern side of the island commanding the Golden Gate, whose inner entrance, roughly two and a half miles west at Point Cavallo, was just barely within the two and a half mile reach of Alcatraz guns.
The only access to the island, which featured steep cliffs around most of its shore, was from a pier on the northeast side commanded by a brick and stone casemate featuring 11 cannon embrasures. From the pier, the only access to the heights of the island-and except for the pier area the island was almost all heights-was up a narrow road through sally port guarded by infantry rifles and three flank howitzer embrasures. On the slopes near the top were officers' quarters, the lighthouse, storehouses, and many other frame structures, but the crowning fortification, on the island's summit, was 'The Citadel,' a massive, fortified barracks.
Just as Alcatraz was unique as an island fortress in America, the 'Citadel' on Alcatraz probably was unique as a building in terms of its military architecture (though no comprehensive study of American military architecture has been done which can prove that point.) It was built of the material typical of seacoast fortifications mounting heavy artillery-brick and stone; it was enclosed by a moat as were many such forts--in this instance a dry moat. Its basic plan was more like that of a palisaded frontier fort, a rectangle with bastions equivalent to blockhouses at two diagonal corners to provide flanking fire along the four walls. But this Citadel, this fortified barracks, was designed to be, defended solely by rifle fire--it did not have a single cannon embrasure, and this is what made it so unusual and possibly unique.
The Alcatraz Citadel had three stories. The first or basement level was sunk below ground level and was surrounded by a dry moat which the army termed a "ditch." This is the only portion of the Citadel which survives. The second level or first story was at ground level, and had access over drawbridges at each end across the dry moat. The basement had rifle embrasures all the way around, the second level had narrow windows which could double as rifle embrasures, and the third level or second story had still slightly wider windows which also could double as rifle embrasures, while the roof provided a forth story of protection, for it was surrounded with a parapet over which infantry could fire at an enemy. The rifle embrasures and windows all were protected by iron shutters which could be closed against hostile fire.
Plans for the Citadel were prepared by 2nd Lieutenant Frederic E. Prime in June 1857 (The first guns on Alcatraz had already arrived and been mounted in the South Battery in 1853.) The Citadel basement was to contain four officers' kitchens, four officers' bedrooms. an officers' storeroom, the company kitchen, a bakery, four storerooms in the enlisted men s section, and a prison room adjoined by one light and one dark cell. The first floor had four officers' dining rooms, four parlors, one servant's room, one company mess room, one reading room for enlisted men, one company office, two sergeants' rooms, one laundresses' kitchen., and two laundresses' bedrooms. The top floor was divided into eight officers' bedrooms, one servant's room, two enlisted men's dormitories or barracks, and two more sergeants' rooms. Built into the counterscarp around the dry moat at the basement level were eight small storage rooms for vegetables, coal, and the like, and a privy for enlisted men. By June 1858 the excavation for the building and its moat were completed, and its brick walls were going up. It was finished by the end of November 1859.
The guns on Alcatraz never fired a shot in anger, and neither did the Citadel. That they never did may have been a mark of their success as a deterrent to enemy attack on San Francisco Bay, for during the Civil War the Confederate raider Shenandoah did attack the Union commercial whaling fleet in North Pacific waters, and without the deterrent of strong defense of the Golden Gate, that ship could easily have slipped into the Bay to shell the city and perhaps capture Mother Lode gold held in its banks, diverting it to finance the failing Confederacy. After the war, the importance of Alcatraz as a fort waned as larger and longer range guns were developed, and as defense batteries correspondingly progressively farther west toward the seaward approaches. In 1882, the Citadel was converted into six sets of officers' quarters and served thereafter as a sort of officers apartments building.
The importance of Alcatraz as a prison grew and when plans were drawn up for the first truly permanent military prison building, it was to be located at the summit of the island in place of the Citadel. Late in 1908 demolition of the upper two stories of the old Citadel began; the basement level and dry moat were to remain as foundations and basement for the new prison. Major Reuben B. Turner, the commandant and construction quartermaster, also used the two old granite entrances to the Citadel as entrances in the new prison, and salvaged an ornate iron stairway similar to those at Fort Point to run from the hallway between the cell block and mess hall down to the lavatory. Thus roughly a third of the old Citadel survives, which has led over the years to rumors of mythical Spanish dungeons beneath the penitentiary. And to the extent that the basement level of the old Citadel once contained a prison room and two cells, there was perhaps a grain of truth even to that old wives' tale.
The Citadel, circa 1869 (Photgraph courtesy of John Martini)
The Citadel circa 1893 (Photograph courtesy of John Martini)
Alcatraz's Lighthouse with the Citadel in the background (Photograph courtesy of the National Archives)


Originally Published in 1981 for the annual meeting of the Council on Abandoned Military Posts. Reprinted with permission of the author
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