At approximately 10:00 P.M. two companies of the Twentieth Massachusetts, Companies A and K commanded by Captain Henry Tremlett, were sent into the woods under the cover of darkness for picket duty to protect the Union flank and determine the position of the Confederate army. The woods were covered with the bodies of dead and wounded Confederates from the battle at Savage Station, and they needed to proceed with extreme caution in the inky darkness to avoid revealing their proximity to the Confederates.
At 11:00 P.M. Captain Tremlett crept silently through the dark woods to where the Twentieth Massachusetts was stationed. To his great distress, Tremlett found that his regiment and the Union Army had retreated, leaving his two companies to keep the Confederates at bay. Tremlett silently ordered his men to fall in and march. As they plunged through mud and stumbled over tree stumps in the darkness, they eventually reached the Williamsburg Road and followed it until they found the road to White Oak Bridge. Following that road, they rejoined their regiment around 3:00 A.M.1
The Twentieth Massachusetts Regimental History records the severity of the danger to Companies A and K as follows:
It was a most dangerous and disagreeable duty that fell to the lot of these two companies, for they were the very last of the rear guard of the army, and were liable at any moment to be attacked and overwhelmed or cut off and captured.2
1George A. Bruce, The Twentieth Regiment of Massachusetts Volunteer Infantry 1861 - 1865 (Cambridge, Massachusetts: The Riverside Press, 1906), 118-119. Richard F. Miller, Harvard's Civil War: A History of the Twentieth Massachusetts Volunteer Infantry (Lebanon, New Hampshire: University Press of New England, 2005), 144-45. Henry Tremlett, "Letters," Association of Officers of the Twentieth Massachusetts Regiment, Reports, Letters and Papers Appertaining to Twentieth Massachusetts Volunteer Infantry, vol. 2, p. 169-72, Twentieth Massachusetts Special Collection, Boston Public Library, Boston, Massachusetts.
2George A. Bruce, The Twentieth Regiment of Massachusetts Volunteer Infantry 1861 - 1865 (Cambridge, Massachusetts: The Riverside Press, 1906), 119.