The tactic the Union Army used to slow Confederate advances was Artillery bombardment.

During the Battle of Gettysburg, Union forces strategically placed their artillery on elevated terrain, including Cemetery Ridge, allowing them to unleash powerful fire on advancing Confederate troops. This bombardment focused on clusters of soldiers, disrupting their formations and inflicting heavy casualties. The Union artillery's capacity to deliver concentrated fire at pivotal moments, particularly during assaults such as Pickett’s Charge, was instrumental in undermining Confederate offensives and ultimately aided in the Union's successful defense.