The confederate troops, controlled by General Albert Sidney Johnston marched, 40,000 troops strong out on April 6, 1862. They attacked an unprepared Union Army at Pittsburg Landing near the Tennessee River. The Confederate Army under General Ulysses S. Grant, was overwhelmed and decided to drop back to what’s known as the “Hornets Nest.” The Confederates initial attempts to destroy the “Hornets Nest” were repelled, by the better cover of the Union. Artillery killed or wounded many. General Johnston was mortally wounded and replaced by P.G.T. Beauregard. The Union army held through the night until they got reinforcements out numbering the Confederates. They made a counter-offensive winning the battle. In this battle, was the bloodiest single