To counteract McClellan’s forces at the Battle of Antietam, Lee employed flanking movements.

Understanding the need to leverage his smaller forces effectively, Lee sought to maneuver his troops to outflank Union positions, particularly during critical moments of the battle. This strategy aimed to create confusion and disrupt Union lines, allowing his men to engage from advantageous angles. Despite the challenges posed by the Union's defensive positions, Lee's tactics showcased his ability to adapt and attempt to offset McClellan's numerical superiority, although the overall outcome remained costly for both sides.