The first day at Gettysburg set the stage for the war's costliest battle, forcing Union forces onto defensive high ground that proved decisive.
Key Facts
- Date
- July 1, 1863
- Union Army
- Army of the Potomac (Maj. Gen. George G. Meade)
- Confederate Army
- Army of Northern Virginia (Gen. Robert E. Lee)
- Union general killed
- Maj. Gen. John F. Reynolds
- Battle phases
- Three distinct phases throughout the day
- Union final position
- Cemetery Hill south of Gettysburg
Location
Cause → Event → Consequence
Confederate forces under Gen. Robert E. Lee were advancing through Pennsylvania when isolated Confederate units of Maj. Gen. Henry Heth's division moved toward Gettysburg, likely seeking supplies. They encountered dismounted Union cavalry under Brig. Gen. John Buford, whose delaying action drew in infantry reinforcements from both armies and transformed a chance encounter into a full engagement.
The battle unfolded in three phases on July 1, 1863. Morning Confederate advances down Chambersburg Pike were repulsed by arriving Union I Corps infantry, though Gen. Reynolds was killed. By afternoon, Confederate Second Corps attacked from the north, overrunning Barlow's Knoll. In the final phase, renewed assaults from north and west collapsed the Union line, forcing Federal troops through Gettysburg with heavy casualties.
Outnumbered Union forces retreated to Cemetery Hill and other high ground south of Gettysburg, establishing strong defensive positions. Lt. Gen. Richard Ewell declined to press the attack despite discretionary orders from Lee, a decision historians have long debated. The Union's possession of the high ground shaped the remaining two days of the battle and contributed to the eventual Confederate defeat at Gettysburg.
Belligerents & Mobilization Analysis
Side A
1 belligerent
Maj. Gen. George G. Meade, Brig. Gen. John Buford, Maj. Gen. John F. Reynolds.
Side B
1 belligerent
Gen. Robert E. Lee, Lt. Gen. A.P. Hill, Lt. Gen. Richard S. Ewell.