The Battle of Gettysburg (July 1-3, 1863) Published on 8.6.2024 In June 1863, after two years of indecisive fighting, General Lee decided to strike the heart of the Union and invade Pennsylvania to reach Washington, at the head of a Confederate army of 75,000 men. Unfortunately for him, he had to come up against the 95,000 soldiers of General George Gordon Mead's Army of the Potomac near the small town of Gettysburg.