Guard House near Langley, courtesy of Harpweek, LLC

On a wall of the CIA’s Visitor Control Center at the Agency’s main entrance, there is an enlarged drawing that appeared in Frank Leslie’s Illustrated Newspaper during the Civil War. The drawing shows a small wooden building identified as “Guard House Near Langley”—a reminder that Langley, now known as McLean and the location of CIA Headquarters, once was known as the location of a Union Army outpost.

During the winter of 1861-1862, troops of the 2nd, 3rd, 4th, 5th, and 6th Vermont Infantry regiments were stationed at Camp Griffin, which encompassed much of what is now eastern McLean, including part of what would become the Agency’s Headquarters compound.

At the beginning of the war, in a move to protect Washington, Federal troops had seized Virginia land across the Potomac from the capital. Later, the army set up Camp Griffin there. The encampment lasted for about six months and was replaced by Fort Marcy, one of 48 forts built around Washington.

The Vermont troops were among the 70,000 Union soldiers who assembled at Bailey’s Crossroads on November 20, 1861 for a grand review. “As far as the eye could reach there was nothing but lines of bayonets and uniformed men,” one of the Vermonters wrote in his journal. The troops passed in review before President Lincoln, Major General George B. McClellan, and guests who included Julia Ward Howe.

When Mrs. Howe headed back to Washington, troops returning from the review passed by her coach, singing marching songs that included “John Brown’s Body.” A fellow passenger suggested to Mrs. Howe that she might consider writing better lyrics for the stirring melody. She awoke before dawn the next day in her room at the Willard Hotel and wrote the words of “The Battle Hymn of the Republic.” On her journey back from the grand review, she had seen the “watch-fires of a hundred circling camps,” and some of those fires were flickering on what are now the grounds of the CIA Headquarters.

Men of the Vermont regiments were assigned picket duty between the camp and the Potomac River—“standing,” as one wrote, “on the outer verge of all that is left of the American Union.” They eventually broke camp to fight at Antietam, Gettysburg and in the Battle of the Wilderness. They also served in the Shenandoah Valley, where on October 19, 1864, they helped to win the Battle of Cedar Creek, near Middletown, Virginia.

In 1992, the Agency commemorated the anniversary of the battle with a ceremony at Headquarters. “We feel a strong tie to the soldiers of Cedar Creek,” said Robert M. Gates, Director of Central Intelligence. “There is a key lesson to be learned” from the battle, he said: “intelligence is decisive, not only in preparing for war, but in defending the peace.” He noted that Confederate Major General John Gordon had personally gathered intelligence as he stood at the summit of Massanutten Mountain and observed the Union troops gathering in the valley below. “He pinpointed the location of Union trenches and artillery positions,” Gates said. “he saw the weakness in the Union’s left flank. And he observed that Union guards—so necessary for advanced warning—were not deployed around the fringe of the Union camp.”

Armed with this intelligence, Gordon launched a surprise attack on the morning of October 19, routing the Union troops. In the afternoon, Union forces regrouped under Major General Philip Sheridan and defeated the Confederates–who withdrew–ending the South’s control of the Shenandoah Valley.