The Battle of Bull Run ended the initial "Ninety-Day War" between the Union and Confederate armies. Though not a decisive battle militarily, it had significant psychological and political consequences for both sides. Later, the Peninsula Campaign led by General George McClellan against Richmond was ultimately unsuccessful due to various compromising factors. The Seven Days Battles in June-July 1862 drove McClellan's Army of the Potomac back from the Peninsula in a costly failure for the Union.
The Battle of Antietam in September 1862 halted General Robert E. Lee's invasion of Maryland and forced his retreat, though it resulted in a high casualty toll. While not a clear Union victory, it allowed President Lincoln to issue the Emancip