The Union Corps that attacked the Confederate left flank on the second day of the Battle of Gettysburg was the Fifth Corps.

Under the leadership of General George Sykes, the Fifth Corps was instrumental in bolstering Union defenses and mounting attacks against Confederate troops entrenched on elevated terrain. On July 2, 1863, their actions were pivotal in securing the Union line amid fierce combat, especially in critical locations such as the Wheatfield and Little Round Top. This synchronized offensive was essential in thwarting Confederate progress and played a significant role in the Union's defensive triumph.