American Battlefield Trust’s map of the Battle of Gettysburg - Longstreet’s Attack
Lee took note of the strong Union position on the hills south of Gettysburg. As at Chancellorsville with Jackson, Lee favored an attack against the flank of the Union line, somewhere on the lower ground at the south end of Cemetery Ridge. Early on July 2, he ordered a reconnaissance to determine if the high ground near the Round Tops was occupied. When informed that it was not, Lee conceived a plan to sweep north up the Emmitsburg Road to roll up the Union left.
The spearhead of the attack would be Longstreet’s First Corps, arriving on the battlefield that morning. Additional brigades of Richard Anderson’s division from A. P. Hill’s corps were attached to Longstreet, giving him nearly 15,000 men for the attack. Longstreet waited for Lafayette McLaws’ division to arrive that afternoon, and then commenced a lengthy and misdirected march behind Seminary Ridge to conceal the movement of his infantry. John B. Hood and McLaws finally moved their divisions eastward around 4:00 p.m. toward the Union III Corps along and behind the Emmitsburg Road.
The attacking brigades would advance in sequence from south to north to pull Union reinforcements south from the area of Cemetery Hill, the keystone of the Union position. If the plan worked, Meade’s left would be crushed with no reinforcements available to support the climax of the attack on the Union center. As Lee had hoped, Union reinforcements from the II and V Corps flowed toward the Peach Orchard, Wheatfield and Little Round Top to meet the Confederate advance.