No 1: Report of Maj. Gen. George B. McClellan, U. S. Army, commanding Army of the Potomac, dated August 4 1863
Early in the afternoon of the 5th the advance of each column was brought to a halt; that of Heintzelman (Porter’s division), in front of Yorktown, after overcoming some resistance at Big Bethel and Howard’s Bridge; that of Keyes (Smith’s division) unexpectedly before the enemy’s works at Lee’s Mill, where the road from Newport News to Williamsburg crosses Warwick River.
The progress of each column had been retarded by heavy rains on that day, which had made the roads almost impassable to the infantry of Keyes’ column and impassable to all but a small portion of the artillery, while the ammunition, provisions, and forage could not be brought up at all.
When General Keyes approached Lee’s Mill his left flank was exposed to a sharp artillery fire from the farther bank of the Warwick, and upon reaching the vicinity of the mill he found it altogether stronger than was expected, unapproachable by reason of the Warwick River and incapable of being carried by assault.
The troops composing the advance of each column were during the afternoon under a warm artillery fire, the sharpshooters even of the right column being engaged when covering reconnaissances.
It was at this stage and moment of the campaign that the following telegram was sent to me:
April 4, 1862.
By direction of the President, General MacDowell’s army corps has been detached from the force under your immediate command, and the general is ordered to report to the Secretary of War. Letter by mail.
The President having promised, in an interview following his order of March 31, withdrawing Blenker’s division of 10,000 men from my command, that nothing of the sort should be repeated—that I might rest assured that the campaign should proceed with no further deductions from the force upon which its operations had been planned—I may confess to having been shocked at this order, which, with that of the 31st ultimo and that of the 3d, removed nearly 60,000 men from my command, and reduced my force by more than one-third after its task had been assigned, its operations planned, its fighting begun. To me the blow was most discouraging. It frustrated all my plans for impending operations. It fell when I was too deeply committed to withdraw. It left me incapable of continuing operations which had been begun. It compelled the adoption of another, a different, and a less effective plan of campaign. It made rapid and brilliant operations impossible. It was a fatal error.
It was now, of course, out of my power to turn Yorktown by West Point. I had therefore no choice left but to attack it directly in front, as I best could with the force at my command.
Reconnaissances made under fire on that and the following day determined that the sources of the Warwick River were near Yorktown, commanded by its gnus, while that stream, for some distance from its mouth on the James River, was controlled by the Confederate gunboats; that the fords had been destroyed by dams, the approaches to which were generally through dense forests and deep swamps, and defended by extensive and formidable works ; that timber felled for defensive purposes and the flooding of the roads, caused by the dams, had made these works apparently inaccessible and impossible to turn ; [p.11] that Yorktown was strongly fortified, armed, and garrisoned, and connected with the defenses of the Warwick by forts and intrenchments, the ground in front of which was swept by the guns of Yorktown. It was also ascertained that the garrisons had been and were daily being re-enforced by troops from Norfolk and the army under General J. E. Johnston. heavy rains made the roads to Fort Monroe impassable and delayed the arrival of troops, ammunition, and supplies, while storms prevented for several days the sailing of transports from Hampton Roads and the establishment of depots on the creeks of York River near the army.
The ground bordering the Warwick River is covered by very dense and extensive forests, the clearings being small and few. This, with the comparative flatness of the country and the alertness of the enemy, everywhere in force, rendered thorough reconnaissances slow, dangerous, and difficult; yet it was impossible otherwise to determine whether an assault was anywhere practicable or whether the more tedious but sure operations of a siege must be resorted to.
Official Records of the Rebellion: Volume Eleven, Chapter 23, Part 1: Peninsular Campaign: Reports, pp.10-11
web page Rickard, J (20 June 2006)