Both the Union and the Confederacy developed an army Signal Corps during the Civil War. The job of the Signal Corps in both the North and South was to quickly and accurately relay information and orders between the commanders of different units within the two forces (which was especially crucial during battles). The main way they did this was through the use of a flag system called wig-wag (not to be confused with semaphore), which was invented by Albert J. Meyer, an army surgeon, shortly before the war.
In wig-wag, either a single flag (during the day) or lantern (at night) was moved in set patterns to the right or left to represent letters, abbreviations, and word substitutes. There were seven flags of varying sizes and colors that could be used depending on the distance the message was to be passed and what the terrain was like. Wig-wag was a faster way to communicate than sending a courier on horseback and was especially useful in areas where a telegraph system was not set up. Both sides used codes to try to keep their messages secret, but they were often able to crack the other’s codes, until the Union instituted the use of a cipher disc.
If signalmen were in a fairly permanent location, a tall wooden signal tower would often be built; otherwise, members of the Signal Corps used whatever was available to help them reach a higher elevation, including hilltops, rooftops, church steeples, and trees. The distance between signal stations was usually determined by how far the signalmen could see with a spyglass and was not often more than 6 miles. Because signalmen were in such highly visible locations, they were often the target of sharpshooters.
In addition to passing and receiving messages with wig-wag, signalmen also sometimes served as observers, scouts, and couriers. Although the Union and Confederate Signal Corps shared many of the same duties, the Confederate Signal Corps was also involved in espionage, including engaging in covert operations and developing a network of informants.
Fold3 has many records and images related to the Union and Confederate Signal Corps. Below are just a few examples:
- Photo of officers of the Signal Corps of the Army of the Potomac
- Photo of a signal station at the camp of the 13th New York Cavalry, at Prospect Hill, Virginia
- Confederate general order creating the Signal Corps in the South
- Photo of Union signal tower overlooking Antietam battlefield, Elk Mountain, Maryland
- Confederate reimbursement form for “one spy glass, for the use of Signal Corps”
- Letter from man requesting appointment to Confederate Signal Corps
- Union signal tower near the Appomattox River, Bermuda Hundred, Virginia
- Confederate cipher used by their Signal Corps with directions on how to use it
- Photo of Union Signal Corps men at the Washington, D.C., Central Signal Station
- Letter from Admiral Farragut commending the work of two Union Signal Corps officers
Do you have ancestors who served in the Signal Corps? Tell us about them! Or search Fold3 for more information about the Signal Corps during the Civil War.