Ancestry ∗ Biography ∗ History
In the aftermath of their defeat at the First Battle of Bull Run, Union troops had been rushed to the front in great numbers for fear of an incursion on Washington. The Union defeat had been a shock, and Union President Abraham Lincoln replaced then-commander Brigadier General Irvin McDowell with Major General George McClellan. Placed in command of the newly-named Army of the Potomac, McClellan would play an important role in raising a well-trained and organized army, and the troops at Camp Benton were now consumed by daily drills, shooting practice, and strict discipline, including no noise allowed after taps.
Camp Benton was situated outside Poolesville, Maryland, on the east bank of the Potomac River, barely 35 miles from Washington. By this day in American Civil War history, a month had passed since the Twentieth Massachusetts left the capital. The west bank was Virginia, so the river was the boundary between the Union and the Confederate states. The relevant part of the river also had an odd topography; the river at that point doglegs southwest to southeast and splits the Potomac River proper between itself and the Chesapeake and Ohio Canal, with 400-acre Harrison’s Island in between. The Virginia shore of the river was dominated by Ball’s Bluff, a 100-foot cliff.
Henry describes an early October day on the east bank of the Potomac in a letter home:
Edward’s Ferry, Md.
October 6, 1861
Dear folks at home,
Nothing has occurred since I last wrote you until Friday, when the rebels had the impudence to fire 8 or 10 shot and shell across the river. Artillery was immediately sent to the river from Poolesville and sent back 32 shot and shell in return. None of the rebels’ guns did any harm and they withdrew their battery into the woods. . . General Lander detailed my company to march to the river after supper and support the artillery. . . Here we have been ever since bivouacking in the woods, having erected huts to protect us from the dews and rains.
I took a stroll at five o’clock this morning, alone down by the river and again later in the morning, and although there are plenty of rebels in the neighborhood on the other side not one was in sight. Whether they will cross or whether we shall go to meet them I cannot find out nor even find anyone who does know—my own opinion is that they shall not cross.
Henry M. 
War has often been characterized as long periods of boredom punctuated by sudden instances of sheer terror. This was the calm before the storm. For many men new to the army, including Henry, no thoughts, no fears, would prepare them for what they would soon witness and experience.
 Letter from Henry M. Tremlett, captain, Co. A, 20th Mass., in Reports, Letters & Papers Appertaining to 20th Mass. Vol. Inf by Association of Officers of the 20th Massachusetts Volunteer Infantry, 1868, Boston Public Library Rare Books Collection, 2:162–163.
Next: Prelude to Battle
The story of the 20th Massachusetts Volunteer Infantry Regiment is part of my book, The Colonel and the Vicar, available on Amazon.com.