Thank you for the detailed analysis (as always). BTW, Early said he had about 10,000 infantry:
My infantry force did not exceed 10,000, as Breckinridge's infantry (nominally much larger) really did not exceed 2,500 muskets.
Here's what the frontline commander north of Washington said in his report. "Monday morning" would be the morning of July 11, 1864:
From JUNE 23-AUGUST 8, 1864.--Operations in the Shenandoah Valley, Maryland, and Pennsylvania.
No. 24.--Report of Maj. Gen. Alexander McD. McCook, U. S. Army, commanding northern defenses of Washington, of operations July 10-13.
DAYTON, OHIO, July 25, 1864.
COLONEL: I have the honor to submit a succinct report of the military operations in front of Washington, D.C., pending the advance upon it by a portion of the rebel army commanded by General Early.
Reporting in person at the War Department on the morning of July 10, I was directed to report to Maj. Gen. H. W. Halleck. U.S. Army, who assigned me to duty in the Department of Washington, to command a reserve camp to be located on or near Piney Branch Creek, about midway between Washington and Fort Stevens on the north. In company with Lieut. Col. B. S. Alexander, U.S. Engineers, I at once proceeded to examine the ground for the camp, also to make a hasty examination of the fortifications on the north of Washington. Returning at 6 p.m., and receiving my final instructions from Maj. Gen. C. C. Augur, commanding department, I proceeded to Piney Branch, where the Second Regiment District of Columbia Volunteers, Colonel Alexander, and the Ninth Regiment Veteran Reserve Corps, Lieutenant-Colonel Johnston, Captain Gibbs' (Ohio) battery, and Captain Bradbury's (Maine) battery had already reported.
Monday morning discovered the fact that the only troops on the north of Washington were the small garrisons in the forts, small detachments of cavalry in the front, and the troops above mentioned. Hearing of the near approach of the enemy, the idea of a reserve camp was at once abandoned and every man was brought forward and posted in the rifle-pits to the best advantage, and as strong a skirmish line as was prudent established. During the morning several additional regiments of the Veteran Reserve Corps and several detachments of dismounted cavalry reported for duty. They were posted in the rifle-pits on either side of the main road leading to Silver Spring. Captain Berry, of the Eighth Illinois Cavalry, being stationed with his company on the road leading from Silver Spring to Leesborough, dispatched a courier at 10 a.m. the 11th, informing me that the enemy was advancing in force on that road with infantry, artillery, and cavalry. At 12 m. a strong line of the enemy's skirmishers came in view, advancing upon our position. The picket-line at this moment was composed of 100-days' men of One hundred and fiftieth Ohio, and a portion of the Twenty-fifth New York Cavalry (dismounted). Being satisfied that they could not contend favorably against the enemy's line, were ordered to fall back slowly, fighting, until they reached the rifle-pits. Fire was then opened at proper points upon our line, and the enemy was held in check until the dismounted of the Second Division of the Cavalry Corps, Army of the Potomac, 600 strong, commanded by Maj. George G. Briggs, Seventh Michigan Cavalry, were made ready to go out, drive the enemy back, and re-establish our picket-line. This was handsomely done about 1.30 p.m., the enemy's skirmishers being forced back, and our line well established at 1,100 yards in front of the works. The enemy not developing any force other than their skirmish line, affairs remained in this condition until evening. About 3 p.m. Maj. Gen. H. G. Wright, U.S. Volunteers, commanding the Sixth Army Corps, reported to me at Fort Stevens, informing me that the advance of his corps would be up in a short time. I directed him to furnish a force 900 strong of this veteran corps for picket duty during the night, constant skirmishing being kept up between the lines until after dark on the 11th instant. At 9 p.m. Brig. Gen. M. C. Meigs, Quartermaster-General U.S. Army, reported at Fort Stevens with about 1,500 quartermaster employés, armed and equipped. They were at once ordered into position near Fort Slocum, placed on right and left in rifle-pits. At 10 p.m. Colonel Price reported with about 2,800 convalescents and men from hospitals, organized into a provisional brigade composed of men from nearly every regiment of the Army of the Potomac. They were ordered into position in rear of Fort Slocum, as information received led me to believe that the enemy would demonstrate farther to our right.
At 12.30 a.m. on the 11th the following telegraphic order was received:
Major-General Gillmore, U.S. Volunteers, with a portion of the Nineteenth Corps, is assigned to command the line from Fort Lincoln to Fort Totten. Brig. Gen. M. C. Meigs, Quartermaster-General, to command the line from Fort Totten to Fort De Russy. Brig. Gen. M.D. Hardin, U.S. Volunteers, to command from Fort De Russy to Fort Sumner, inclusive. The Sixth Corps, Maj. Gen. H.G. Wright, U.S. Volunteers, commanding, to be held in reserve, and the entire line, and troops to be commanded by Maj. Gen. A. McD. McCook, U.S. Volunteers.
This order was complied with, with the exception to hold the Sixth Corps entire in reserve. I deemed it absolutely necessary that the immediate front should be picketed by experienced men.
At dawn on the morning of the 12th the sharpshooters of the enemy opened fire upon our skirmish line, which had been intrenched during the night. This fire was kept up from both lines during the day. The enemy, on retiring their line on the evening of the 11th, seized and retained possession of a house on the right of the Silver Spring road, situated on an elevated piece of ground, surrounded by an orchard and large shade trees (Rives), which afforded excellent cover for sharpshooters, and commanded our advance line. They also posted sharpshooters in Mrs. Lay's house to the left of the road. From these two points our skirmish line was very much annoyed by the enemy, they killing and wounding about 30 of our skirmishers during the day. I determined these two points must be carried. General Wright was ordered to furnish a brigade to make the assault (as I had failed to carry these points with Captain Beattie's sharpshooters, of General Getty's division, Sixth Corps). Brig. Gen. Frank Wheaton, U.S. Volunteers, was ordered to direct the movements of the assaulting troops. These troops having gained their position previous to assault at about 6 p.m., the two positions held by the enemy were vigorously shelled from Fort Stevens. Then at a signal Wheaton's troops dashed forward, and, after a spirited contest, gained the ground. This attack developed new forces of the enemy that had been concealed in a ravine beyond Mrs. Lay's house, and in the depression beyond the copse on the right of the road. The enemy's line was re-enforced by at least a brigade, the contest was kept up until after dark, we having gained all the ground desired, and rude intrenchments were thrown up upon it.