Thomas Mauser

Among those Union Army generals who served and fought during the American Civil War, the name of Grenville Mellen Dodge is not well-known. In comparison to the wartime achievements of, among others, Ulysses S. Grant, William Tecumseh Sherman, and Philip Sheridan, General Grenville Dodge’s accomplishments were of a more modest nature. Nevertheless, he made his own significant contribution to the Union victory over the Confederacy.

A native of Massachusetts, Grenville Dodge graduated with a degree in civil engineering in 1851 from Norwich University in Vermont and began work as a surveyor for several railroads. He eventually settled in Council Bluffs, Iowa, where he married and continued his railroad surveying work.

Following the outbreak of the Civil War in April 1861, Grenville Dodge was appointed Colonel of the Fourth Iowa Volunteer Infantry Regiment. As the war progressed, Dodge led various Union Army formations in several military engagements, including the Battle of Pea Ridge (March 1862) and the Iuka-Corinth (Mississippi) campaign (September–October 1862). It was during the latter campaign that Dodge suffered several wounds.

Following his recovery from those wounds, Grenville Dodge was promoted to brigadier-general in June 1863 and was assigned the duty of repairing and maintaining the Mobile & Ohio (M&O) Railroad between Corinth, Mississippi, and Columbus, Ohio. His civil engineering and railroad background aided him in his work as he organized and managed a ‘pioneer corps’ of fugitive African-American slaves. It was while working with these fugitive slaves that Dodge witnessed first hand the cruel realities of slavery and was inspired to recruit and establish two African-American infantry regiments – the First and Second Alabama Infantry Regiments of African Descent.

Dodge and his men’s work on the M&O Railroad was often disrupted by the aggressive hit-and-run attacks of the controversial major general, Nathan Bedford Forrest, and his Confederate cavalrymen. In fact, Union-held railroad lines that served as supply routes for the Union armies in Tennessee and Mississippi were frequent targets of Confederate cavalry raids. To counter these hostile attacks, General Dodge ordered his men to build two-story blockhouses at every bridge and station along their portion of the M&O rail line and he assigned company-size Union army units in each blockhouse to provide defensive fire and protection. It was a strategy that ultimately proved successful in dispersing Forrest’s cavalry raids on the M&O railroad.

It was during his time in Corinth, Mississippi, that Grenville Dodge also established a spy network that was to make a significant contribution to the Union war effort. It provided valuable intelligence to senior Union Army leadership about Confederate military movements in Mississippi and Tennessee, including General Grant’s successful Vicksburg campaign in 1863 and General Sherman’s Atlanta campaign in 1864.

His cadre of spies – men, women, fugitive slaves, and Confederates (civilians and military prisoners of war) who sympathized with the Union – were carefully selected by Grenville Dodge. He assigned each spy a unique code name composed of numbers or letters that was known only to himself. He kept these secret code names written on several sheets of papers and carried those sheets with him for the duration of the war, keeping them secret even from his closest aides and subordinates.

During his time as a Union Army spymaster, General Dodge firmly believed that accuracy and uniformity of intelligence information was vital. To that end, he took the utmost care of his spies and trained them extensively. The espionage tasks he told his spies to undertake behind Confederate lines was difficult, indeed dangerous, work. Capture by the enemy meant certain death. Dodge taught his spies that if they were captured by the Confederates they should tell the truth, but never reveal or compromise any Union Army plans or operations.

Each of Dodge’s spies was taught to correctly identify the various Confederate Army formations as well as the different Confederate Army officer ranks. He also taught them how to use studied glances when gathering vital intelligence about the enemy.

During the Civil War, the Union and Confederate armies used railroads to transport their troops. Dodge taught his spies how to calculate the number of Confederate troops being transported by rail – they studied and memorized the different types and capacities of rolling stock used by the Confederates, counted the numbers and types of rolling stock in each rebel troop train that was under observation, and multiplied them by the capacity of each type of rolling stock to accurately calculate Confederate troop strength.

General Dodge’s covert intelligence operations involved sending two spies – each traveling on their own (and unknown to the other) and supplied with gold and Confederate currency to bribe Confederate soldiers and civilians  – to the same enemy location. The spies’ subsequent reports were then compared, thus deterring his spies from collaborating and turning in false or misleading reports. Dodge also questioned fugitive slaves and Confederate prisoners concerning the enemy location that was being spied on by his men and compared the information they provided him with what was contained in his spies’ reports. If all the sources matched, Dodge would forward his intelligence report to the senior Union Army leadership. However, if the sources did not match, Dodge destroyed his spies’ reports and sent another spy to the enemy location in question.

Dodge’s communications with his spies were conducted indirectly through the spies’ relatives who lived behind Confederate lines, and it was they who delivered the encrypted reports to him directly. Dodge made certain that his spies remained behind enemy lines for the duration of the war because he felt it would be difficult, even dangerous, for them to cross Confederate lines. His spies were paid not from the Union Army payrolls, but from the proceeds of the sale in the North of contraband Confederate cotton.

Promoted to the rank of major-general in June 1864, Grenville Dodge successfully commanded first a division and then a corps in General William T. Sherman’s Union Army of the Tennessee during the Atlanta campaign. Dodge continued to use his extensive spy network to provide valuable intelligence to General Sherman, and it was General Dodge who sent Union spies into Atlanta to spy on Confederate defenses. It was also during the Atlanta campaign that he suffered a near-fatal head wound when a Confederate sniper shot him while he was looking through a Union army observation peep-hole toward the Confederate entrenchments.

General Grenville Dodge’s successful military leadership during the American Civil War led General Ulysses S. Grant to call him “a most capable soldier,” and inspired General William Tecumseh Sherman to call General Dodge “a brick,” meaning someone who was reliable and steadfast. His remarkable leadership as a Union Army spymaster during the Civil War made General Grenville Dodge fittingly stand out among his fellow Union Army officers, and earned him the respect of Generals Grant and Sherman. A most capable soldier, indeed.