The War fever of 1861-62 saw a flood of volunteers in the north to suppress the Great Rebellion, and one of the newly formed regiments in the border state of Maryland was the Third Regiment Infantry. Although organized in Baltimore, Maryland the regiment was something of a marriage to Maryland's east and west. Companies formed in Washington County at Williamsport, Maryland, were joined with Baltimore companies to complete the organization in early 1862. From Maryland's eastern shore, one company of nine-month volunteers organized in Easton, Maryland, also served for a time in the regiment. Although the majority of the soldiers were Maryland natives, a substantial minority of the Third Marylanders were German and Irish immigrants who had settled in the Baltimore area.
The Regiment was sent to the Shenandoah Valley in May, 1862 and took part in the many marches up and down the valley. Although the Third Maryland had been in a number of minor skirmishes with rebels, they did not see the elephant (the Civil War euphemism for battle) until the small but bitterly fought battle at Cedar Mountain, a few miles south of Culpeper, Virginia, in August, 1862. The very next month they saw more heavy fighting in the Civil War's most costly single day of battle at Antietam. The next year the regiment suffered its worst single day of losses in May, 1863 at the Battle of Chancellorsville when they were ordered to support the federal right wing during Lee and Jackson's famous victory over Hooker.
Following Lee's army during his second invasion of the north, the Third Maryland saw the elephant once more on Culp's Hill at Gettysburg. That fall the regiment, along with the rest of the Twelfth Corps, was transported by railroad west to Tennessee where they spent the winter guarding the railway lines which supplied the beleaguered federal troops at Chattanooga. While there, most of the men veteranized by re-enlisting for the duration of the war. Part of the agreement was that the men who re-enlisted received a 30-day furlough home. So, in January they returned by railroad to Baltimore while those members of the Third Maryland who had chosen to resist the temptation of re-enlistment served out their three-year terms in Tennessee. There, the 60 man detail participated in Sherman's Atlanta campaign the following spring, guarding ammunition trains and Hooker's headquarters until the term of enlistment's ran out that fall.
Instead of re-united with their detachment in Tennessee following their furlough, the Third Maryland Regiment, now bearing the title Veteran Volunteers was transferred to General Burnside's Ninth Corps. There, they participated in Grant and Lee's spring
and summer slugfest through northern Virginia at the Wilderness, Spotsylvania, North Anna, Cold Harbor, and finally to Petersburg. There the highly mobile campaign settled into a bitter 10-month siege. By June, 1864 the regiment's numbers had been whittled down by death, desertion, and disease until they were officially redesignated a battalion (roughly half a regiment). From their original one thousand men at the beginning of the war they reached a low point of only 56 men in the field at the time they participated at the famous Battle of the Crater in July, 1864.
New recruits replenished their numbers somewhat as the Third Maryland continued to participate in Grant's envelopment of Petersburg, seeing action through the fall months of 1864 at the Weldon Railroad in August and Poplar Grove Church in September. The last major fight in which they participated was at Fort Stedman, which was Lee's desperate and unsuccessful attempt to break the stranglehold at Petersburg in March, 1865.Shortly thereafter Lee fled Petersburg and began the march which would end at Appomattox Court House.
With the war over, the Third Maryland returned to the Washington DC area where they participated in the Grand Review of May 23, a massive pageant of marching troops through downtown Washington, DC. Wrapping up their final weeks of service by guarding the railway lines between Laurel and Hyattsville, the Third Maryland was disbanded on July 31, 1865. By the official count the regiment lost during service eight officers and eighty-three enlisted men killed and mortally wounded. Four officers and one hundred thirty enlisted men also died by disease. The regiment never lost their colors, and five members received the Medal of Honor.