The Telegraph
The telegraph was first used in the Crimean War, but its use as a means of command and control was truly born in the American Civil War. Reports of battles and the movements of the increasingly large armies of the Union were monitored by Abraham Lincoln, who frequently visited the War Department to read the messages as they came in, and directed many of the responses. Cavalry from both sides often targeted telegraph lines to disrupt communications, and to listen to the messages being sent to and from enemy commanders. The telegraph communication systems were built as the war went on, when it began most communications were still via messengers.
When the South seceded there was no telegraph in the War Department. Nor were there telegraphs for the most part in the headquarters in the field. As Union and Confederate Armies concentrated in Northern Virginia, Andrew Carnegie – yes that Andrew Carnegie – built a rail and telegraph line from the War Department towards the front, but it was still ten miles short of the Union lines when the first battle of Manassas was fought in 1861. Messengers from the front carried information to the end of the line where it was transmitted to the War Department and into the hands of the President.
The telegraph allowed Lincoln to monitor the positioning and movements of the troops through the reports, and he in many instances sent orders directly to his commanders. When it became evident that Lee was invading the North in 1863, the commander of the Army of the Potomac, Joseph Hooker, telegraphed that the movement of Lee’s troops offered an opportunity to take Richmond, the Confederate capital. Lincoln responded that Hooker’s goal should be the destruction of Lee’s army, rather than the capture of the Confederate city. When Hooker subsequently followed Lee’s army too slowly for Lincoln, the President fired him and replaced him with George Meade just before Gettysburg.
The telegraph also changed the way the war was reported by the correspondents from the newspapers and periodicals that traveled with the armies and wired back stories of the battles, in many instances as they were taking place. Readers in New York or Philadelphia could follow the Union Army as it battered its way towards Richmond, and telegraphed reports of the trench warfare around Petersburg and Richmond were daily occurrences in the newspapers. Many reporters were granted access to the US Military Telegraph Corps facilities in order to file stories early in the war, a practice discouraged by both Lincoln and Grant.
The US Military Telegraph Corps built the lines which followed the troops as they advanced. The subsidiary Telegraph Construction Corps built over 15,000 miles of wires over land, buried, and submerged across rivers and streams. Cipher codes were developed and implemented as the war went on, and codes were often changed. It was the US Military Telegraph Corps – who were civilians other than the most senior leaders – that rebuilt the telegraph system in the South, which was almost completely destroyed by the end of the war. After the war the system built by the Military Telegraph Corps was sold to private telegraph companies in the North and South, one of which was Western Union.