Fort Corcoran
Fort Corcoran was a wood-and-earthwork fortification constructed by the Union Army in northern Virginia as part of the defenses of Washington, D.C. during the American Civil War. Built in 1861, shortly after the occupation of Arlington, Virginia by Union forces, it protected the southern end of the Aqueduct Bridge and overlooked the Potomac River and Theodore Roosevelt Island, known as Mason's Island.
The fort was named after Colonel Michael Corcoran, commander of the U.S. Fighting 69th Infantry, Irish Brigade 69th New York Volunteer Regiment, one of the units that constructed the fort.
Fort Corcoran was home to the Union Army Balloon Corps and the headquarters of the defenses of Washington south of the Potomac River, and served throughout the war before being dismantled in 1866. Today, no trace of the fort remains, although the Arlington County government has erected a historical marker at its site.
Early history of the Civil War in Northern Virginia
Before the outbreak of the Civil War, Alexandria County, the closest Virginia county to Washington, D.C., was a predominantly rural area. Originally part of the District of Columbia, the land now comprising the county was retroceded to Virginia in a July 9, 1846 act of Congress that took effect in 1847. Most of the county is hilly, and at the time, most of the county's population was concentrated in the town of Alexandria at the southeastern corner of the county. In 1861, the rest of the county largely consisted of scattered farms and plantations, the occasional house, fields for grazing livestock, and Arlington House, owned by Mary Custis, wife of Robert E. Lee.Following the surrender of Fort Sumter in Charleston, South Carolina, on April 14, 1861, the new American president Abraham Lincoln declared that "an insurrection existed" and called for 75,000 troops to be called up to quash the rebellion. The move sparked resentment in many other southern states, which promptly moved to convene discussions of secession. The Virginia State Convention passed "an ordinance of secession" and ordered a May 23 referendum to decide whether or not the state should secede from the Union. The U.S. Army responded by creating the Department of Washington, which united all Union troops in the District of Columbia and Maryland under one command.
Brigadier General J.F.K. Mansfield, commander of the Department of Washington, argued that Northern Virginia should be occupied as soon as possible in order to prevent the possibility of the Confederate Army mounting artillery on the hills of Arlington and shelling government buildings in Washington. He also urged the erection of fortifications on the Virginia side of the Potomac River to protect the southern terminuses of the Chain Bridge, Long Bridge, and the Aqueduct Bridge. His superiors approved these recommendations, but decided to wait until after Virginia voted for or against secession.
On May 23, 1861, Virginia voted by a margin of 3 to 1 in favor of leaving the Union. That night, U.S. Army troops began crossing the bridges which link Washington, D.C. to Virginia. The march, which began at 10 p.m. on the night of the 23rd, was described in colorful terms by the New York Herald two days later:
Image:Civil-war-logo-2.jpg|thumb|Union soldiers cross the Long Bridge during the occupation of Northern Virginia following that state's secession from the Union.
There can be no more complaints of inactivity of the government. The forward march movement into Virginia, indicated in my despatches last night, took place at the precise time this morning that I named, but in much more imposing and powerful numbers.
About ten o'clock last night four companies of picked men moved over the Long Bridge, as an advance guard. They were sent to reconnoitre, and if assailed were ordered to signal, when they would have been reinforced by a corps of regular infantry and a battery....
At twelve o'clock the infantry regiment, artillery and cavalry corps began to muster and assume marching order. As fast as the several regiments were ready they proceeded to the Long Bridge, those in Washington being directed to take that route.
The troops quartered at Georgetown, the Sixty-ninth, Fifth, Eighth and Twenty-eighth New York regiments, proceeded across what is known as the chain bridge, above the mouth of the Potomac Aqueduct, under the command of General McDowell. They took possession of the heights in that direction.
The imposing scene was at the Long Bridge, where the main body of the troops crossed. Eight thousand infantry, two regular cavalry companies and two sections of Sherman's artillery battalion consisting of two batteries, were in line this side of the Long Bridge at two o'clock.
For the most part, the occupation of Northern Virginia was peaceful. The town of Alexandria was the sole exception. There, as Colonel Elmer E. Ellsworth, commander of the New York Fire Zouaves, entered a local hotel to remove the Confederate flag flying above it, he was shot and killed by James Jackson, the proprietor. Ellsworth was one of the first men killed in the American Civil War.
Planning and construction
Over 13,000 men marched into Northern Virginia on the 24th, bringing with them "a long train of wagons filled with wheelbarrows, shovels, &c." These implements were put to work even as thousands of men marched further into Virginia. Engineer officers under the command of then-Colonel John G. Barnard accompanied the army and began building fortifications and entrenchments along the banks of the Potomac River in order to defend the bridges that crossed it. By sunrise on the morning of the 24th, ground had already been broken on the first two forts comprising the Civil War defenses of Washington — Fort Runyon and Fort Corcoran. Fort Corcoran was named after Colonel Michael Corcoran, commander of the 69th New York Volunteer Regiment, one of the units that constructed the fort. The 69th New York, part of the famed Irish Brigade, went about its work with high spirits, exemplified by the actions of Father Thomas Mooney, the 69th's chaplain. After the fort's cannon were emplaced, Mooney baptized them and was promptly recalled by New York's bishop, who took a dim view of the sacrilegious action.Despite the limited nature of the two forts, Barnard reported that the work was difficult. "The first operations of field engineering were, necessarily, the securing of our debouches to the other shore and establishing of a strong point to strengthen our hold of Alexandria. The works required for these limited objects were nevertheless, considering the small number of troops available, arduous undertakings."
In the seven weeks that followed the occupation of Arlington and the beginning of work on Fort Corcoran, Barnard and his engineers were forced to focus virtually all of their effort on Corcoran and Runyon, owing to the limited resources available. By the time Barnard was beginning to focus his efforts on tying Corcoran and Runyon into an entire belt of fortifications, his engineers were drawn off by the approach of the Confederate Army and the incipient First Battle of Bull Run.
Expansion and renovation
Following the Union defeat at Bull Run, panicked efforts were made to strengthen the forts built by Barnard in order to defend Washington from what was perceived as an imminent Confederate attack. Many of makeshift trenches and blockhouses that resulted would later be renovated and expanded into permanent defenses surrounding Fort Corcoran. On July 23, President Abraham Lincoln and Secretary of State William Seward visited Fort Corcoran in an effort to revive morale after the defeat at Bull Run.Image:24-pound siege gun.jpg|thumb|Artillerymen pose with their 24-pounder siege cannon at Fort Corcoran
On July 26, 1861, five days after Bull Run, Maj. Gen. George B. McClellan was named commander of the military district of Washington and the Army of the Potomac. Upon arriving in Washington, McClellan was appalled by the condition of the city's defenses, despite the hurried efforts in the wake of the Union defeat:
In no quarter were the dispositions for defense such as to offer a vigorous resistance to a respectable body of the enemy, either in the position and numbers of the troops or the number and character of the defensive works... not a single defensive work had been commenced on the Maryland side. There was nothing to prevent the enemy shelling the city from heights within easy range, which could be occupied by a hostile column almost without resistance.
Large numbers of disorganized troops sat in hastily dug trenches in Arlington, awaiting a Confederate assault. Fort Corcoran itself served as the rallying point for several battered artillery units, filling the fort well beyond capacity. An informal report on July 29, 1861, indicated Corcoran had far more than its planned 12 guns and 180 artillerymen. The report listed "12 8-inch seacoast howitzers, seven 24-pounder barbette guns, two 12-pounder field guns, and two 24-pounder howitzers." Manning these guns were over 200 dedicated artillerymen and many soldiers from the De Kalb regiment who had been cross-trained in artillery. Naturally, these facts meant the fort was severely overcrowded, and the report indicated that "...the field batteries are in very unsatisfactory condition, many of them..."
To remedy the situation at Corcoran and the other forts defending Washington, one of McClellan's first orders upon taking command was to greatly expand the number and size of the forts defending the city. In regards to improving Fort Corcoran, Barnard reported, "A belt of woods was felled through the forest in front of Arlington and half-sunk batteries prepared along the ridge in front of Fort Corcoran and at suitable points near Fort Albany, and a battery of two rifled 42-pounders was established on the heights near the distributing reservoir above Georgetown to sweep the approaches to Fort Corcoran." Portions of this work were done by troops under the command of William Tecumseh Sherman, eventual commander of the Military Division of the Mississippi, who was encamped in a location near the fort following the defeat at Bull Run.
Image:69th New York Militia.jpg|thumb|Officers of the 69th New York Volunteer Regiment pose with a cannon at Fort Corcoran in 1861.Michael Corcoran at left
On October 25, 1862, Edwin M. Stanton, the Secretary of War, ordered that a civilian commission be established in order to study the defenses of Washington, D.C. and make recommendations on improving those defenses as needed. The final report was delivered to Secretary Stanton on December 30, 1862, and several portions dealt with Fort Corcoran, one of the largest forts defending Washington at the time. The commission recommended that a new work be constructed on a ridge above and behind Forts Tillinghast and Cass in order to "...give great additional strength to Fort Corcoran, enabling it to be held, even should the two works in its front fall...." In addition, the commission recommended that additional bombproofs be constructed in Fort Corcoran in order to provide protected refuge for the entire garrison.
In the years that followed the completion of the fort, numerous telegraph lines were laid between Fort Corcoran, War Department offices in Washington, and other forts in Northern Virginia. According to a July 1863 report on the operations of the military telegraphs in the Army of the Potomac, six telegraph lines ran between Fort Corcoran and Washington, five between Corcoran and Fort Ethan Allen, two between Corcoran and Alexandria, and one each to two observation points southwest of the fort. Throughout the remainder of the war, Fort Corcoran remained an important communications center for the entire Arlington Line system of defenses, eventually connecting to over 30 miles of telegraph wire at the time of Robert E. Lee's surrender.