[2] After their early service at Fortress Monroe in Virginia, the 29th was attached, in the spring of 1862, to the Army of the Potomac during the Peninsular Campaign as part of the famed Irish Brigade.

In the fall of 1863, IX Corps took part in the Knoxville Campaign which resulted in the defeat of Confederate forces in eastern Tennessee.

The spring of 1864 saw the IX Corps and the 29th Massachusetts once again returned to duty with the Army of the Potomac, just in time to take part in the Overland campaign and the siege of Petersburg.

But in their haste to reach the capital, these regiments had departed without a full complement of ten companies as required by army regulations.

[5] This strategically important foothold in Virginia allowed Union forces to control the major waterway of Hampton Roads.

[10] During the winter and early spring of 1862, the 29th was deployed on various minor expeditions near Fortress Monroe, Newport News and Norfolk, Virginia.

On March 8 and 9, the regiment was present during the Battle of Hampton Roads, a naval engagement fought primarily between the USS Monitor and the CSS Virginia.

The regiment helped man a land battery during the engagement, and the men of the 29th were amazed by the new ironclad vessels and the changes they brought to naval warfare.

[11] In the middle of March, once again at Fortress Monroe, the 29th witnessed the arrival of the Army of the Potomac, commanded by Major General George B. McClellan.

As the campaign became bogged down outside the Confederate capital, additional troops were called for and the 29th Massachusetts departed Hampton Roads on June 7, 1862.

[13] Traveling by steamboat up the York River, the 29th arrived at White House Landing and marched to the battle front on June 8, 1862.

"[15] Historian Daniel Callaghan quotes period sources describing the "unlikely matching of ancient political foes," and the manner in which the men of the 29th tolerated the Irish-born commander of the Irish Brigade, Brig.

[19] Following the failure of the Peninsular campaign, elements of the Army of the Potomac were shipped to northern Virginia to provide assistance to Union Maj. Gen. John Pope.

After these failed, the II Corps, including the Irish Brigade, was called upon to assault a position near the Confederate center known as the "Sunken Road" or "Bloody Lane."

An accident in the terrain, a small rise in front of the 29th's position, afforded them cover, and their casualties were lighter than those of the other regiments of the brigade.

Armstrong argues that Barnes was reluctant to leave this advantageous ground, a factor which may have contributed to the failure of the Irish Brigade's charge.

[28] While in camp in Falmouth in late November, the officers of the 29th learned that Meagher had arranged for a green Irish Brigade flag to be presented to the regiment, recognizing their role as "honorary Irishmen" and their bravery during the Battle of Antietam.

[34] In early June, most of the IX Corps was transferred to the command of Maj. Gen. Ulysses Grant who required reinforcements in the siege of Vicksburg, the last major Confederate stronghold on the Mississippi River.

[36] While digging trenches, the 29th was exposed to heavy artillery and sharpshooter fire from the Confederates, but the regiment suffered only one casualty during the siege.

They missed the first group of steamships to depart for Cincinnati and had to wait three weeks, until August 12, with other regiments at a camp in Milldale, Mississippi, near Vicksburg.

As the regimental historian wrote, "Deaths were very frequent among the troops here during this time, burial parties were almost constantly engaged, and the funeral notes of the fife and drum could be heard nearly every hour in the day.

"[40] Burnside gathered his Army of the Ohio in the vicinity of Lexington, Kentucky, in late August 1863 in preparation for an invasion of eastern Tennessee.

[41] Prior to the march, half of the men in the 29th were on the sick list as a result of their service in Mississippi, including Barnes, who took an extended leave and returned for a time to Massachusetts.

[46] Following this Union victory and the retreat of Longstreet's troops to Virginia, the 29th was stationed in mid-December 1863 at Blaine, Tennessee, about 20 miles (32 km) northeast of Knoxville.

Over the next nine days, the regiment built breastworks and served on picket duty until June 12 when IX Corps rapidly marched to the outskirts of Petersburg, Virginia, in preparation for an assault on that city.

According to the regimental historian, "They had scarcely emerged upon the open plain, when the whole crest of the Confederate works was fringed with fire and smoke; grape, canister, and musketballs filled the air.

In the fall of 1864, the 29th served uneventful duty along the Petersburg siege lines and was eventually, in November, assigned a garrison post in Battery 11, a small, unfinished ravelin (detached fortification) outside of Fort Stedman.

Stedman was one of many earthen fortifications built along Union lines during the siege, and was only 150 yards from the Confederate trenches—the narrowest distance between the two armies.

[57] On March 25, 1865, the regiment fought in the Battle of Fort Stedman, the Confederate Army's final offensive during the Siege of Petersburg.

Before dawn on March 25, Confederate troops achieved complete surprise and easily occupied Fort Stedman entering the rear sally port almost unchallenged.