1. At the time of Gettysburg, the Army of Northern Virginia, under the command of General Robert E. Lee consisted of three corps and one cavalry division. Confederate corps were larger than Union corps.
I Corps - Lt. General James Longstreet
II Corps - Lt. General Richard Ewell
III Corps - Lt. General A.P. Hill
Cavalry Division - Major General James Ewell Brown (Jeb) Stuart
Lee traveled and camped with Longstreet mostly.
2. At the time of Gettysburg, the Army of the Potomac, under the command of Major General George G. Meade consisted of 8 corps (7 infantry corps and 1 cavalry corps.)
I Corps - Major General John Reynolds
II Corps - Major General Winfield Scott Hancock
III Corps - Major General Daniel Sickles
V Corps - Major General George Sykes
VI Corps - Major General John Sedgewick
XI Corps - Major General Oliver Howard
XII Corps - Major General Henry Slocum
Cavalry Corps - Major General Alfred Pleasanton [the cavalry corps was a "combined force" of approx. 8,000 horse and 3,000 infantry.]
Links go to photographs of the generals. All pictures public domain. Thank you Wikipedia.
Confederate Corps were larger than Union Corps. At Gettysburg, the total confederate forces numbered about 75,000 and Union around 97,000; about 172,000 men engaged in the battle of Gettysburg. They were all there by day 2.
The journey of the Armies: Fredericksburg to Gettysburg.
After the battle of Chancellorsville, the armies engaged again at Fredericksburg. Lee left cavalry at Fredericksburg, but slipped out with his three corps and went west from Fredericksburg, then crossed the Rappahannock and headed north. Stuart's Cavalry followed Lee. As Lee's three infantry corps continued north, there was a major cavalry engagement between Pleasanton (Union) and Stuart (Confederate) at a place called Brandy Station. Stuart then followed Lee north for a while, then (at Lee's orders) cut back south and east and around the (by then following) Union Army. The Union Army shadowed Lee as Lee continued north, staying between Lee and Washington/Baltimore. Stuart got around the Union army and headed north, but farther east than he had expected to be (because the Union army was spread further east than expected), Stuart coming only a few miles outside Washington, then continuing north through Maryland and eventually up to York and over to Carlisle in Pennsylvania. Always, the Union army was between Stuart and Lee.
Lee had crossed the Rappahannock with his main army on June 6, and on June 30, the day before the battle of Gettysburg began, Stuart was between York and Carlisle, to the north of Lee. After the first day's battle at Gettysburg, two men from Stuart's cavalry appeared at Gettysburg in the late evening and met with General Lee. They had been sent down from Carlisle by Stuart to find out what was happening, since he had word of fighting in Gettysburg. Lee sent them back to tell Stuart to come down to Gettysburg from Carlisle at once. That was the first Lee really knew that Stuart was even still alive. Stuart arrived in the afternoon of the second day's battle of Gettysburg with Lee's cavalry. [Other accounts say that it was Lee who sent out 10 couriers to spread out and find Stuart, in the evening following day one, each with sealed orders for Stuart to come to Gettysburg, and that it was one of these couriers who found Stuart. One way or the other, Stuart's cavalry arrived at Gettysburg from Carlisle on the afternoon of the second day.] Stuart had hoped to meet up with Ewell's Corps at Carlisle, but missed them as Ewell had already departed south to Gettysburg. Stuart bombarded the Carlisle barracks then headed south as well.
It is about 30 miles from Carlisle to Gettysburg. From Fredericksburg in Virginia to Gettysburg, Pennsylvania (today on the highway) is 110 miles.
Here is where the combatants were on June 30, the day before the battle of Gettysburg began:
Stuart and the confederate cavalry were between York and Carlisle in Pennsylvania.
Lee had continued to concentrate his forces, and the concentration was in full progress on June 30, Lee moving with Longstreet's I Corps from Chambersburg to Cashtown. Lee and Longstreet would have been at Cashtown (just west of Gettysburg) on June 30. A.P. Hill's III Corps would have also converged near Cashtown and would be moving parallel with Longstreet eastward to Gettysburg. Ewell would have been moving down from Carlisle to the north, and would be closing in on Gettysburg from that direction on June 30. (It would be one of Hill's advance divisions, General Heth, who would make first contact with the union cavalry in the early morning of July 1.)
Longstreet (and Lee) were by now at Cashtown, the corps still coming up. (It took a long time to march that many men over those roads, even at eight abreast, or so, it made for a column miles and miles long.) As the battle developed, more and more units began arriving.
Ewell was just north of Gettysburg. It would be the influx of the forward units of Ewell's II Corps from the northwest which would help further change the balance of power and push the Union forces back off McPherson's Ridge, past the town, and up Culp's Hill and Cemetery Ridge at the end of day one.
2. Union Forces:
The Army of the Potomac was scattered and individual corps commanders did not receive Meade's orders to concentrate on Gettysburg until late on day one or, in some cases, well after the first day's battle was over. Sedgewick's VI Corps, for example, had to force march - 16,000 men and supply trains - all night and most of day 2 from 30-some miles down in Maryland. The Army of the Potomac, however, got up more and more and was completely in place by late in the day of day 2. General Lee did not resume the battle until about 4 pm on day two, so that delay worked in favor of the Union army's hurried concentration.
General Meade had received word of a battle going on at Gettysburg from General Reynolds' courier. He sent the trusted and competent General Winfield Scott Hancock immediately to Gettysburg to decide where to deploy the Union Army, staying behind to prepare orders and send out couriers to the commanders of each Corps to come at once to Gettysburg. After sending orders to his commanders to concentrate the Army of the Potomac, General Mead and his staff finally left for Gettysburg. Meade arrived on the field much after day one's battle had concluded, at about 3 a.m. on day two, and set up his command headquarters. Lee had his headquarters across the field, on the backside of Seminary Ridge, near the Cashtown road.
My next Gettysburg post will be a timeline or summary of the entire 3-days of Gettysburg. Then we can speak of individual events in the battle in subsequent separate posts. I do want to post on other topics in between these, though, to perhaps keep the attention of followers of this blog who are not as interested in Gettysburg as I am.
I encourage you to comment on things you believe are incorrect in my posts, and give any additional facts you want to give.