|June 30, 11:00 a.m.||Gamble's brigade (1/1/Cavalry) and Devin's brigade (2/1/Cavalry) arrive in Gettysburg and occupy a line along McPherson's Ridge, crossing the Cashtown road, northwest of town. Brig. Gen. John Buford, commanding 1st Cavalry Division, is in overall command.|
|June 30, 11:30 a.m.||Pettigrew's
Brigade (Pettigrew/Heth/Third) encounters the Union
cavalry at McPherson's Ridge and withdraws to Cashtown,
arriving late in the afternoon.
Buford reports the Confederates' presence to Maj. Gen. John F. Reynolds, commanding the left wing of the Army of the Potomac.
|June 30, late afternoon||Maj. Gen. Henry Heth requests permission from Lt. Gen. A.P. Hill (commanding Third Corps) to advance to Gettysburg the next morning. Hill grants permission without reference to Gen. Robert E. Lee, commanding the Army of Northern Virginia, although later he informs Lee of Heth's advance.|
|June 30, evening||Buford posts Gamble's brigade on McPherson's Ridge and Devin's brigade north of town, near Blocher's Run.|
|July 1, 4:30 a.m.||Confederate skirmishers from Maj. Gen. Robert Rodes's Division (Rodes/Second) encounter Devin's pickets about five miles north of Gettysburg on the Carlisle road near Keckler's Hill.|
|July 1, 5:00 a.m.||Heth's Division departs Cashtown, heading for Gettysburg, followed by Maj. Gen. Dorsey Pender's Division (Pender/Third).|
|July 1, 7:00 a.m.||Gamble's pickets report the advance of Heth's division to Buford.|
|July 1, 7:30 a.m.||Heth's
lead unit (Archer/Heth/Third) encounters Gamble's
pickets, near Marsh Creek, and steady skirmishing
A staff officer from I Corps encounters Buford just as firing breaks out; Buford sends word of the fighting to Reynolds via this officer.
|July 1, 8:00 a.m.||Buford
orders Devin to move to Gamble's line, leaving his
pickets in place to the north of Gettysburg, and deploys
his division in line of battle along McPherson's Ridge.
Gamble sends reinforcements to his picket line, now
engaged on Herr Ridge.
Under the temporary command of Brig. Gen. Abner Doubleday, I Corps departs Moritz Tavern, moving to Gettysburg on the Fairfield Road. Reynolds accompanies the lead division. At about the same time, Maj. Gen. O.O. Howard's XI Corps departs Emmitsburg, heading for Gettysburg on the Emmitsburg and Taneytown Roads.
|July 1, 8:30 a.m.||Word reaches Lt. Gen. Richard S. Ewell (commanding Second Corps) of the engagement at Gettysburg. He changes the direction of march of his corps, which has been moving to Middletown, towards Gettysburg.|
|July 1, 9:00 a.m.||Heth decides to deploy his division into line of battle, delaying his advance by about half an hour. Brig. Gen. James Archer's Brigade occupies the right of his line, Brig. Gen. Joseph Davis's Brigade (Davis/Heth/Third) the left. The other brigades of Heth's division are not yet up.|
|July 1, 9:30 a.m.||Heth advances against skirmishers covering Buford's main position on McPherson's Ridge.|
|July 1, 10:15 a.m.||Reynolds,
riding ahead of Doubleday's column, arrives at Seminary
Ridge and meets Buford. Reynolds assumes command of the
Union forces on the field.
Heth's advance encounters Buford's main line of defense.
|July 1, 10:40 a.m.||Brig. Gen. James Wadsworth's division (1/I) deploys on Seminary Ridge and advances to the relief of Buford's division on McPherson's Ridge. Brig. Gen. Lysander Cutler's brigade (2/1/I) relieves Devin's line; Brig. Gen. Solomon Meredith's Iron Brigade (1/1/I) relieves Gamble's.|
|July 1, 10:50 a.m.||Reynolds is shot and killed while supervising the placement of the Iron Brigade. Doubleday assumes command of the Union troops.|
|July 1, 11:30 a.m.||Heth's
brigades are repulsed by the I Corps infantry, losing
prisoners (including General Archer) on their right flank
and, on their left flank, at the railroad cut in
McPherson's Ridge. The intensity of fighting diminishes.
Howard, with his leading division (1/IX, commanded by Brig. Gen. Francis C. Barlow) , arrives in Gettysburg, and learns of Reynolds's death.
|July 1, 12:00 noon||Howard assumes command of the Union forces at Gettysburg. Brig. Gen. Thomas A. Rowley's division (3/I) and Brig. Gen. John C. Robinson's division (2/I) arrive on McPherson's Ridge. Doubleday places them to support and extend to both sides the position of Wadsworth's division on the ridge.|
|July 1, 1:00 p.m.||Barlow's division (1/XI) and Brig. Gen. Carl Schurz's division (3/XI) arrive at Gettysburg, and take up a line north of town, reaching from Barlow's Knoll to Oak Ridge. They do not, however, completely connect with the I Corps line facing west on Oak Ridge. Their deployment takes about one hour. Howard notifies Maj. Gen. Dan Sickles (commanding III Corps) and Maj. Gen. Henry Slocum (commanding XII Corps) of the battle.|
|July 1, 1:30 p.m.||Maj. Gen. George G. Meade, commanding the Army of the Potomac, having learned of Reynolds's death about noon, orders Maj. Gen. Winfield Scott Hancock to turn command of his II Corps over to Brig. Gen. John Gibbon, and ride to Gettysburg and take command.|
|July 1, 2:00 p.m.||Brig.
Gen. Adolph von Steinwehr's division (2/XI) arrives.
Rather than commit it to his main line, Howard deploys it
on Cemetery Hill as a reserve.
Lee and Hill arrive on the field in rear of Heth's division.
|July 1, 2:30 p.m.||Intense fighting resumes as Rodes's Division advances against the junction between I and XI Corps. His attack is poorly conducted, his brigades fight one by one, and he is repulsed.|
|July 1, 3:00 p.m.||Heth
askes Lee for permission to attack in support of Rodes.
Lee refuses him at first, but Heth renews his request and
Lee grants it. Pettigrew's Brigade attacks the Union
left; it is repulsed but it pins down I Corps.
Slocum's XII Corps departs Two Taverns, approaching Gettysburg on the Baltimore Pike; Slocum has learned of the fighting at Gettysburg at about 1:00 but has not moved for two hours.
|July 1, 3:30 p.m.||The
head of Maj. Gen. Jubal Early's Division (Early/Second)
arrives on the Heidlersburg Road just as Brig. Gen.
George Doles's brigade (Doles/Rodes/Second) is attacking.
Early puts his leading brigade, under Brig. Gen. John B.
Gordon (Gordon/Early/Second) in on Doles's left. Gordon
overwhelms the Union's rightmost brigade under Col.
Leopold von Gilsa (1/1/XI) and the Union right flank is
Pender's Division, supported by the fresh brigades of Heth's Division, follows up the attack of Pettigrew's Brigade and turns the Union left flank, forcing I Corps to retreat to Seminary Ridge.
|July 1, 4:00 p.m.||The continuing advance of Pender's and Heth's Divisions forces I Corps to fall back from Seminary Ridge through Gettysburg. At roughly the same time, the remainder of Early's Division arrives on the Union right and forces XI Corps to withdraw through the town also. Federal Gen. Francis Barlow (1/XI) is left severely wounded on the field.|
|July 1, 4:15 p.m.||Maj. Gen. Richard H. Anderson's Division (Anderson/Third) arrives in the rear of the Confederate position on McPherson's Ridge, but Lee decides to hold him in reserve and the division goes into bivouac without receiving orders to join the fight.|
|July 1, 4:30 p.m.||Hancock
arrives at Gettysburg and encounters Union troops
retreating onto Cemetery Hill. He meets Howard. Hancock
claims to have taken command at this time; Howard
maintains that he gave Hancock command of only part of
the Union troops on the field at that time. The dispute
is never satisfactorily resolved.
Hancock and Howard rally the survivors of I and XI Corps on Cemetery Hill, basing their new lines on the position occupied by von Steinwehr earlier in the day, and on the artillery of I and XI Corps, most of which is still effective.
Lee moves onto Seminary Ridge. He observes the disorder of the Union troops moving through Gettysburg but also observes the building position on Cemetery Hill, and the exhausted condition of Pender's and Heth's Divisions. Not knowing the condition of Ewell's troops, he sends Ewell an order to take Cemetery Hill "if practicable." Ewell receives this order shortly afterwards, but decides an attack is not practicable, and no assault is made.
|July 1, 5:00 p.m.||Confederate
troops from Second Corps enter Gettysburg, capturing many
prisoners from XI Corps.
Longstreet arrives at Gettysburg in advance of his troops. Lee orders Longstreet to bring his entire corps as far east as possible. Longstreet orders night marches, but his troops are still on the west side of South Mountain (Pickett is still at Chambersburg, on rear guard duty in the absence of any cavalry) and his march is delayed by the presence of Johnson's division and the Third Corps trains ahead of him on the same road. Nonetheless, Hood and McLaws go into camp for the night near Marsh Creek, about four miles from Gettysburg.
|July 1, 5:30 p.m.||Slocum arrives on Cemetery Hill, and assumes command of the Union army. Hancock begins taking orders from Slocum immediately; Howard does not do so until about 7 p.m. Brig. Gen. Alpheus Williams's division (2/XII) originally occupies Benner's Hill, but the retreat of XI Corps to Cemetery Hill makes that position useless and Williams is recalled to occupy Culp's Hill on the right of Cemetery Hill. Brig. Gen. John Geary's division (1/XII) occupies Cemetery Ridge, just north of the Round Tops.|
|July 1, 6:00 p.m.||Meade orders the entire Union army to move to Gettysburg.|