Wherein McClellan sends the Pennsylvania Reserves to check on a key spot on the Potomac
"It seems pretty well settle that I will be Comdr in Chf within a week," Maj. General George B. McClellan crowed to his wife, Mary Ellen, writing from Lewinsville, Virginia on October 19, where he was spending time with the division of "Baldy" Smith. McClellan had heard the results of a secret cabinet meeting the day before, where the President had determined to act on the offer to resign by his general-in-chief, Bvt. Lt. General Winfield Scott, which had been pending for months now.
Secretary of the Navy Gideon Welles recorded the meeting in his diary:
The Presdt. read to us a draft to a letter to Gen S. (delicately and handsomely written) importing that Gen S. had expressed a wish to be retired, under the act, and only witheld [sic] it at the Presdt.'s request; that he would no longer object--That he would still, sometimes, need his advice--not so often as to burden him--and was disposed to deal generously by the Genl.'s military family...Scott's military family meant the officers he had helped promote and whose careers he had helped advance, such as Brig. General Irvin McDowell. But foremost in Scott's mind would have been Henry Wager Halleck. Halleck was nicknamed "Brains" because of his intellectualism and Scott became enamored of him because of his translations of French military strategy and efforts to turn the rough American army into a leader in the realm of military science. When the Civil War broke out, Scott made sure that Halleck was made a major general in the regular army, fourth in rank behind himself, McClellan, and John C. Fremont. Then Scott sent Halleck to Missouri to clean up the mess Fremont had made.
"Genl Scott proposes to retire in favor of Halleck," McClellan told Mary Ellen. "The Presdt & Cabinet have determined to accept his retirement, but not in favor of Halleck. The old ____'s [sic] antiquity is wonderful & lasting." Welles wrote down no such comment about Halleck, but hindsight suggest McClellan's information was correct. By tradition, the general-in-chief was always the longest serving major general, anyway, so to name Halleck to the position while McClellan and Fremont were still on active duty would be unprecedented.
"The enemy have fallen back on Manassas--probably to draw me into the old error," McClellan added, almost as an afterthought. "I hope to make them abandon Leesburg tomorrow."
"I had just seated myself down to write you a nice long letter," George Meade had written his wife on the evening of October 18, "when orders came to march to-morrow, requiring me to stir about and give the requisite directions."
McClellan had assigned guarding of the upper Potomac River to four divisions: those of Maj. General Nathaniel P. Banks at Harper's Ferry and Brig. General Charles P. Stone at Poolesville, both north of the river; and those of Brig. Generals George McCall and "Baldy" Smith south of the river. When Stone, who was charged with keeping an eye on the Confederate force at Leesburg had reported their sudden withdraw on October 17, McClellan concluded that they must be falling back to a more defensible position behind Bull Run - not the least because he had been in a fight with Scott about whether placing Smith and McCall's divisions south of the river was a good idea. Now McClellan appeared to have a chain of cause and effect proving his own wisdom.
But McClellan's assumption wasn't entirely accurate. The commander of the Confederate brigade at Leesburg was Colonel Nathan "Shanks" Evans, and he had withdrawn without permission. Almost immediately after his superior, General G.T. Beauregard, found out, he had sent discretionary orders for Evans to reoccupy Leesburg, if it was still possible, and mildly chastising him for making such a decision without consulting him. To keep Banks from uniting his large division with McCall's and Smith's divisions on the south bank of the Potomac was of the "utmost military importance," Beauregard's adjutant told Evans, "and you will be expected to make a desperate stand, falling back only in the face of an overwhelming enemy." It was so important because the Confederate army was not back in position behind Bull Run, but in a much more exposed position stretching from Union Mills Ford up to Centreville, and then back to Stone Bridge, and a flank attack from Leesburg would be devastating.
"The object of our expedition," Meade explained to his wife, "is to advance some twelve to fifteen miles to the front, to reconnoiter the country, and also with the hope of cutting off some of the troops coming down from Leesburg."
Not realizing that Evans' withdraw wasn't part of a larger fall-back, but being unwilling to risk a large-scale engagement, McClellan had decided to send George McCall to investigate Leesburg (in Civil War terms, march them close enough to the defensive positions and see what shot at them). McClellan suspected that even in the best case he Confederates would have left some soldiers in Leesburg, if only to slow down a Union advance. So he had decided to send McCall's entire 12,000 man division (known as the Pennsylvania Reserves), including Meade's brigade.
The men stepped off from their camp at Langley on the morning of October 19. Their target was Dranesville, a small town on the Leesburg Pike [VA 7] that today has been subsumed by the sprawl of Leesburg. With three brigades and three batteries of artillery (around 18 guns, depending on the composition), McCall was careful to protect his way back. Advancing down the Georgetown Pike [VA 193], he left his third brigade at Difficult Creek [Difficult Run, not far from the entrance to Great Falls Park], to be an anchor on the Potomac River, so his flank could not be turned. Continuing down the pike, he left Meade's brigade near the community of Great Falls, and proceeded with his remaining brigade, under Brig. General John F. Reynolds, beyond Sugar Creek [Sugarland Run, the advance was to roughly near today's Dulles Town Center].
View Ball's Bluff, October 19 in a larger map
McClellan went to visit McCall at his headquarters with Reynolds' brigade that evening, and ordered him to pull it back to Dranesville and to plan on returning to Langley on October 20. According to later accounts, McCall requested and received permission to stay an extra day, so that his engineers could finish making maps of the area, which they expected to need in case of action around Leesburg. Reynolds' men had tripped a Confederate picket-line (and killed one), revealing to McClellan that there was still some force in Leesburg and telling him all he needed to know, but McCall's request made sense as well, as long as he was on his way back to Langley on October 21, in order to restore the defensive cordon along the Potomac that had been broken by moving the entire division.
As night fell on October 19, Meade still continued to stir about and give his requisite directions, this time sending out the proper night-time pickets and preparing his brigade to be the link between Reynolds' and the one on the Potomac River, so that the division couldn't be cut off by the Confederates the next day. Meanwhile, further south, Evans was reversing his stealthy movement of a few days earlier and rushing his men back to Leesburg.