Share This Article

It was early April 1862, and a partially filled yellowish balloon was drifting just above the treetops outside Yorktown on the Virginia Peninsula. Leaning out of the basket dangling below was Union Major General Fitz John Porter—who was, for the moment, ignoring the fact that the balloon was completely out of control. Balancing his looking glass on the basket’s edge, Porter peered down at Confederate positions over which the wobbly bladder conveniently passed. Eventually the balloon veered back over Union lines, and Porter brought the contraption crashing down safely onto a tent (which was fortunately empty), to the cheers of Army aeronaut Thaddeus Lowe and a host of giddy Federals.

Balloon reconnaissance was just one of an assortment of intelligence-gathering methods employed by Civil War armies. Porter’s was one of a half-dozen of the octopuslike creations used by Maj. Gen. George McClellan, who was better known for his employment of Allan Pinkerton’s spies—and for his misuse of the information they provided during his Peninsula campaign. The Confederate Army also launched a couple of rudimentary airships before ditching the idea. By late 1863, the ever-present threats of foul weather and enemy artillery fire had combined to end the brief career of Civil War balloons.

In the absence of organized intelligence-gathering bodies, information-hungry commanders counted on tried and true sources such as prisoners, deserters, newspapers—especially Northern papers whose editors and reporters often valued their exclusive “scoop” above the national good—and the civilian network. Pondering a move to Richmond from Gordonsville, Va., in June 1862, for instance, “Stonewall” Jackson sought to clarify a rumor of Yankee troops approaching from the Rapidan River.

“The chief mode adopted was characteristic,” Lt. Gen. D.H. Hill later wrote, “it was to send out by night an intelligent private citizen, thoroughly acquainted with the Rapidan people and country, as his scout. This gentleman came back, after thorough inquiry, with the news that the rumor was unfounded.”

Federal troops, too, picked up enemy secrets in Unionist or occupied territory, often from slaves and free blacks. A Virginia slave, for instance, told at least one Union officer ahead of time that Confederate forces would evacuate Yorktown, which they did on May 3, 1862. Fighting for most of the war in territory populated by citizens loyal to their cause, however, naturally gave Southern armies the edge in mining local news.

Southern intelligence further benefited from more effective use of scouts, cavalry and guerrilla units such as Colonel John Mosby’s Partisan Rangers, who excelled at unearthing Federal secrets through direct observation, the capture of baggage trains (which sometimes yielded officers’ personal papers) or by waylaying Federal couriers. The undercover work of scouts and spies, of course, was not fail-safe—a fact that Robert E. Lee discovered in Union-friendly western Maryland.

With no end to the war in sight, the military information game diversified. Signal towers were used increasingly as intelligence posts—which aided Union forces armed with the key to Confederate signals. And while spies worked for each side, the more celebrated moles, such as Elizabeth Van Lew and Rose Greenhow, were less valuable in the long run than the anonymous agents and “false deserters” groomed by the North and South and dispatched to relay false information.

Finally in 1863 an official Federal intelligence unit emerged amid Joseph Hooker’s reorganization of the Army of the Potomac. Largely obscured by Hooker’s more visible changes (such as the creation of the Union Cavalry Corps) and his abrupt departure, the Army’s Bureau of Military Information was the first organized Federal unit dedicated to the gathering and analysis of intelligence. With the aid of a handful of full-time agents and civilian informants, paid out of the War Department’s “Secret Service” fund, Hooker successfully discovered and exploited a gap in Lee’s Fredericksburg lines that allowed him to suddenly threaten the Army of Northern Virginia from the rear in May 1863.

Of course, intelligence meant nothing if it was not used in a timely manner, a fact that was illustrated at Fredericksburg on the morning of December 13, 1862. Hours before that Federal disaster, a captured Rebel offered Hooker (then in corps command) and Maj. Gen. Edwin Sumner “full information of the position and defenses of the enemy.” Ambrose Burnside, the army’s commander, chose not to change his battle plan—and the rest is history.

This article was written by Eric Either and originally published in the April/March 2007 issue of Civil War Times Magazine. For more great articles, subscribe to Civil War Times magazine today!