Civil War Union Brevet Brigadier General. When the Civil War began in April 1861 he joined the 8th Massachusetts Militia regiment, being mustered in as a Private in Company I on April 30, 1861. His regiment served a three-month enlistment in the defenses of Baltimore, Maryland, and he was mustered out on August 1, 1861. In late 1861 he helped recruit the 30th Massachusetts Volunteer Infantry, coming in contact with Major General Benjamin Franklin Butler, who was raising a number of regiments in the state for an expedition to capture New Orleans, Louisiana. General Butler became impressed with Charles Dimon, and promised him an officer’s position. Dimon then joined the 30th Massachusetts, being commissioned 1st Lieutenant and Regimental Adjutant on February 20, 1862. He was with his unit through the Siege and capture of New Orleans, and fought in the August 5, 1862 Battle of Baton Rouge. On October 20, 1862 he was transferred to the 2nd Louisiana (Union) Volunteer Infantry, a regiment that was recruited from Louisiana Unionist and Confederate prisoners of war after New Orleans fell to General Butler. Commissioned Major of the regiment, he served with this unit through the Siege of Port Hudson, Louisiana, but became ill, and was given a medical discharge on June 22, 1863. He was sufficiently recovered by early 1864 to seek out another position in the Union Army, requesting to serve on the staff of his benefactor, General Butler, who was at that time commanding the Army of the James in Virginia. Instead he was commissioned as Major of the 1st United States Volunteer Infantry, a unit made of captured Confederates who had joined the Union Army after swearing allegiance to the United States (called “galvanized Yankees”). Charles Dimon was promoted to Lieutenant Colonel of the unit on April 2, 1864, then to Colonel and commander on August 7, 1864. After some service in North Carolina in the summer of 1864, the 1st United States Volunteers were dispatched to the Dakota Territory amid fears that many would desert and rejoin the Confederate army. Posted as Fort Rice, he and his men endured harsh winter conditions and relations with local Native American tribes that by summer of 1865 had deteriorated to the point where in July 1865 the fort was attacked. Colonel Dimon and his men successfully repulsed the assault. The end of the war in 1865 produced low morale and high desertions for Colonel Dimon’s men, as they were not mustered out like much of the rest of the Union army. In November 1865 Colonel Dimon took the remnants of his command to Fort Leavenworth, Kansas, where he was his men were mustered out on November 27. On March 13, 1865 he had been brevetted Brigadier General, US Volunteers for “gallant and meritorious services”. In the post-war years he gained a position at Benjamin Butler’s United States Cartridge Company in Lowell, Massachusetts, and managed it through the 1870w and 1880s. He was elected Mayor of Lowell twice, and died in office midway through his second term.