Editor's note: Walter Holden, a World War II veteran from Franklin, is an an expert on the Fifth Regiment New Hampshire volunteers. This is Part I of a two-part series on the role of the New Hampshire soldiers at the Civil War Battle of Antietam, fought 150 years ago on Sept. 17, 1862, along Antietam Creek at Sharpsburg, Md. More Americans were killed in a single day of battle at Antietam than at any other time in U.S. history.

On a sunny mid-September afternoon, the Fifth Regiment New Hampshire volunteers strode along as the rear guard of its division. Over the dirt roads of the Maryland countryside they trod through the dust raised by hundreds of men before them. Riding alongside on his horse was their commander, Col. Edward E. Cross. Less than a year before, he had boarded the train at Concord with 1,000 men. Action and disease had whittled down his numbers, but the men left would be called “pure gold” by Gen. Winfield Scott Hancock at Gettysburg.

The brigade commander was Gen. John Caldwell of Maine; the division commander, Gen. Israel Richardson; the corps commander, Edwin Vase Sumner, who at 65 was the oldest corps commander in the army. In the coming battle, two of these men would commit blunders; the third would be killed.

The Army of the Potomac was led by “Young Napoleon,” George B. McClellan, who would sit on a nearby hill, watching and waiting, committing the greatest blunder of all. The battle would be fought with Gen. Robert E. Lee's Army of Northern Virginia.

Approaching the village of Boonsboro, Richardson halted the column and called for Col. Cross to bring forward the Fifth Regiment New Hampshire. One of Cross' officers was Thomas Leonard Livermore, a teenage lieutenant. Livermore described this move in his book “Days and Events: 1860-1866.”

“Our regiment was put into the double-quick to pass to the head of the column,” wrote Livermore. “We went down with our canteens and traps rattling like a mule train and gave to and received many shouts from the Irish Brigade which we passed. We learned that the honor of leading the charge had been given to us in preference to the leading brigade, to their chagrin and our pride.”

The Irish commander, Gen. Thomas Meagher, immediately rode to Richardson and challenged his decision. Richardson roared back: “If I was going to take hell, I should want the Fifth New Hampshire as skirmishers!”

Gen. Richardson told Cross, “Colonel, we have no cavalry nor artillery. Your regiment must act as both. Deploy and sweep the sides of the road.”

The Fifth justified Richardson's trust. Livermore wrote, “Scattering skirmishers had no chance in front of our determined line nearly half a mile long which now swept the country and, with eleven bugles pealing out the commands for the different evolutions, we moved in the finest skirmish we ever had.”

A. D. Richardson of the New York Tribune wrote: “The Rebel pickets were at the end of the street as the head of Richardson's column reached the center of town. Col. Cross's skirmishers went straight forward, and they fell back at once.”

After driving the Confederate rear guard through Keedysville, the Fifth mounted a hill and looked down upon Antietam, “but which was so insignificant then was unknown to us until we had seen it over this crest into the valley,” Livermore wrote.

Less than a mile beyond Antietam Creek, the skirmishers beheld the entire Confederate army, thousands and thousands of soldiers deployed in lines of battle. Pvt. John Melendy of Livermore's company, struck by a shell fragment, became the first Union casualty at Antietam.

Almost immediately, another shell burst over their heads.

The prelude to the great battle was mainly quiet; all day Sept. 16, Gen. Lee gathered his Confederate forces while McClellan watched and waited. His waiting was a mystery to his soldiers on the ground, as well as historians, a great opportunity lost.

The Union artillery had finally arrived; followed by what Cross described as “a fierce artillery duel.” Richardson's division, supporting the guns, lost more than 100 men.

During the night, Caldwell's brigade was awakened and sent to guard McClellan's headquarters.

“I grumbled a great deal at this order for I feared it would deprive us of our share of the battle,” Cross wrote.

The next day, the battle was fought. On the morning of the battle, Cross wrote, he was introduced to McClellan. Like most of the Army of the Potomac at that time, Cross admired McClellan and was willing to excuse him almost anything.

At first, the battle seemed to be going according to plan. Cross climbed to the hilltop to watch the attack by the First Corps, led by Gen. “Fighting Joe” Hooker: “Thousands of scattered rebels were seen breaking from the woods and scudding across the plowed fields, now and then turning to fire. Pressing after them came the long lines of Hooker's gallant corps.”

When Hooker needed support, Gen. Joseph Mansfield led in his Twelfth Corps. When his men faltered, Mansfield rode to the front, where he was immediately shot down and killed. Next to attack was Gen. Edwin V. Sumner, whose long and distinguished career went back more than 50 years. Fifteen weeks earlier at Fair Oaks, his bold eagerness to attack had saved part of McClellan's army from defeat, but this day at Antietam, bulling into battle was disastrous. He led two divisions of the Second; the attack led straight into ambush, and Sumner's men were badly defeated.

Now Richardson's division came down off the hill and into the fray — first the Irish Brigade under Meagher, then the Third Brigade under Col. John Brooke. Finally the First, under Gen. Caldwell, with the Fifth New Hampshire last in line.

Cross wrote that he never felt better in his life and that his men were in good spirits. Livermore was not quite so certain: “Although we were on the offensive apparently, a fair field with no fortifications lay before us, and our enemy seemed at last to be in line of battle before us. Yet, notwithstanding all this, a strange feeling of wonder and restlessness came over me and, likely enough, over many who stood beside me. ... When was the fight to begin? How long would it last? Who would win? Was I to be killed, to be torn with a shell, or pierced by a bullet?”