Coast Defense of the Potomac

Coast Defense of the Potomac insignia (National Archives drawing)

At the turn of the twentieth century Fort Washington was a large military post and headquarters for the Artillery District of the Potomac, a modern defense system that included works on both sides of the Potomac River.

In 1808 a small fort was built to protect the cities of Washington and Alexandria, Virginia. It was destroyed during the War of 1812. Fort Washington was completed in 1824 and armed with large seacoast cannons in 1842. When wood sailing ships mounted smoothbore cannons on their sides, Fort Washington could prevent any enemy from reaching the District of Columbia. During the Civil War, Fort Foote and Battery Rogers were constructed up river and 68 forts were built around the Capital to protect against land attack.

After the Civil War, our government dismantled the circle of forts and sent over a million militiamen home. Fort Washington and Fort Foote were retained as seacoast forts and plans were made to reinforce the outdated structures with heavy guns. In 1875, all work on seacoast fortifications stopped and until 1890 no money was spent to construct or repair any coast defenses.

Smoothbore cannon mounts next to rapid-fire emplacement at Battery White (Photo by Roy V. Ashley)


In 1887, President Cleveland found a treasury surplus. Two years earlier, a Board of Engineers, presided over by Secretary of War William C. Endicott, recommended a new system of seacoast defense that employed heavy steel breech-loading rifled guns, large mortars, rapid fire guns and underwater mines. The entire plan called for the installation of the new defenses at 27 sites along our coast and rivers.


Work did not begin on the new system until Benjamin Harrison became president in 1889. The Fifty-first Congress found a solution to the treasury surplus that had plagued Cleveland during the last two years of his Administration. New public buildings, river improvements and even a pension for the Civil War veterans, that had been promised but not delivered, were among the spending bills introduced and passed by the Congress. Some of the surplus money, $1,221,000 in 1890 and $750,000 in 1891 was appropriated for coast defenses.

Battery Commander's Station at Battery Decauter (Army Signal Corps photo)


The Endicott Board's recommendation for the defense of Washington was thirteen 10 and 12-inch guns and 150 submarine mines. They were to be placed at Fort Washington, Maryland and Sheridan Point, Virginia at an estimated cost of 1.3 million dollars.

On January 11, 1890 a Board of Engineers was ordered to investigate the points and submit a project for the defense. They recommended that most of the defenses be constructed at Fort Washington. Part of their plan was for an underground mine control room to be built on the north end of Fort Washington and at Sheridan Point. Fort Hunt was to receive two 12-inch guns, three 8-inch guns.

Work on the new defenses began with the Mining Casemate, an underground room for firing electrically detonated mines. The following year ground was broken for Battery Decatur but was suspended to await final design of the 10-inch disappearing carriage. Construction resumed in 1896 and the guns were mounted in early 1897. The same year work also began at Sheridan Point later named Fort Hunt in honor of Major General Henry J. Hunt who died in 1889.

Old fort barracks used to store construction material (Army Signal Corps photo)


Lieutenant Colonel Peter C. Haines, president of the Engineer Board planning the defense of Washington described the purpose of the works in a letter of June 26, 1891. "The defensive works at Fort Washington are designed to prevent a hostile fleet from reaching positions within bombarding distance of the Capitol and the Washington Navy Yard. It is scarcely within the range of possibilities that any other than a naval attack would be made on this position. The defenses are therefore designed to resist such attack only."

Rapid-fire guns at Battery James Many (Army Signal Corps photo)


Work on the defenses progressed slowly until the War with Spain in 1898. When the Battleship Maine went down, the Washington defenses consisted of the two guns of Battery Decatur and one gun at Battery Emory. The threat of a Spanish invasion created new interest in defense and work on seacoast fortifications began almost immediately. By 1906, Fort Washington had two mining casemates and eight gun batteries.

Mortar Commander's Station and Fire Commander's Station (Photo by Roy V. Ashley)


The primary armament was designed to fire against the armored sides of ships and included three 10-inch batteries at Fort Washington and an 8-inch battery at Fort Hunt. Battery Decatur was started in 1891 and named for Commodore Stephen Decatur, naval hero of the War of 1812. Work at Battery Emory, named for Major General William H. Emory, commenced in 1897. Battery Humphreys was started in 1898 and named for Major General Andrew A. Humphreys. Battery Mount Vernon, at Fort Hunt boasted three 8-inch guns. One 6-inch battery, Wilkin was started in 1899. Batteries Porter and Robinson, at Fort Hunt carried one 5-inch gun each. These intermediate batteries were for general defense.

The 12-inch mortar battery designed to direct vertical fire at the thin decks of modern war ships was named for Major General Montgomery C. Meigs and started in 1898. It originally had eight 12-inch mortars but later two mortars were removed from each pit

The three rapid-fire batteries at Fort Washington mounted two guns each. Battery White was started in 1898, Smith in 1899 and James Many in 1902. Battery Sater, at Fort Hunt had three 3-inch guns. The rapid-fire guns protect the minefield and fire across the decks of ships to destroy fire control and maneuvering equipment.

Battery Humphreys (Signal Corps photo)


The first military unit to serve the new guns at Fort Washington was Company A, 4th U. S. Artillery who were assigned to Battery Decatur on July 21, 1897. In 1898 Company K, 4th Artillery was assigned to Fort Hunt. In 1901, Company A was re-designated 37th Company, Coast Artillery Corps and remained at the post until 1904. Other units included the 44th, 104th and 116th Companies of Coast Artillery were stationed at Fort Washington

Battery Wilkins (Signal Corps photo)


Until 1917, Fort Washington's defensive works were constantly upgraded by modifying the structures and adding new equipment. Even modern convenience, such as electric lights, telephones and rest rooms were added to the batteries. Additional structures were built to house the meteorology stations, the fire control system and electric power plants. A narrow gage railroad ran from the engineer wharf to each battery.

The new technologies employed in these batteries provided for accurate fire onto any ships attempting to approach Washington from the river. Fire could be directed against ships from the time they rounded Marshall Hall Point until they were well past Fort Washington. However, newer technologies, such as the military aircraft made these defenses obsolete.

Battery Humphreys (Signal Corps photo)


Fort Hunt's guns were removed in 1917 and 1918 and the post became a service school. During World War I three of Fort Washington's 10 inch-guns were removed and sent to Europe for use on railroads. After the war, the 12th Infantry occupied the post and only a caretaker detachment of Coast Artillerymen remained. Finally, in 1939, a detachment of ordnance personnel from Fort Monroe removed the remaining Coast Artillery guns and equipment from Fort Washington and the Artillery District of the Potomac ceased to exist. Only a few concrete shells remain to remind us that the security of our borders was sometimes in doubt and American technology created one of the best coast defense systems in the world.

Last updated: April 10, 2015

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