In the light of dawn, April 6, a small Federal reconnaissance discovered Johnston's army deployed for battle beside the Corinth road, just a mile beyond the forward Federal camps. Storming forward, the Confederates found the Federal position unprotected. Johnston had achieved almost total surprise. By mid-morning, the Confederates seemed within easy reach of victory, overrunning one frontline Union division and capturing its camp. However, stiff resistance on the Federal right entangled Johnston's brigades in a savage fight around Shiloh Church. Throughout the day, Johnston's army pummeled the Federal right, which gave ground but did not break. Casualties upon this brutal killing ground were immense.
Meanwhile, Johnston's flanking attack stalled in front of Sarah Bell's peach orchard and the dense oak thicket labeled the "hornet's nest" by the Confederates. Grant's left flank withstood Confederate attacks for seven crucial hours before being forced to yield ground in the late afternoon. Despite causing heavy casualties and seizing ground, the Confederates only drove Grant towards the river, instead of away from it. The Federal survivors established a solid front before Pittsburg Landing and repulsed the last Confederate charge as dusk ended the first day of fighting.

The Second Day
Shiloh's first day of slaughter also witnessed the death of the Confederate leader, General Johnston, who fell at mid-afternoon, killed by a stray bullet while directing the action on the Confederate right. At dusk, the advance division of General Buell's Federal Army of the Ohio reached Pittsburg Landing, and crossed the river to file into line on the Union left during the night. Buell's arrival, plus the timely look of a reserve division from Grant's army, led by Major General Lewis Wallace, fed over 22,500 reinforcements into the Union lines. On April 7, Grant renewed the fighting with an aggressive counterattack.
Taken by surprise, General Beauregard managed to rally 30,000 of his badly beaten Confederates, and mounted a hard defense. Inflicting heavy casualties on the Federals, Beauregard's troops temporarily halted the determined Union advance. However, strength in numbers provided Grant with a big advantage. By midafternoon, as waves of fresh Federal troops swept forward, pressing the tired Confederate forces back to Shiloh Church, Beauregard realized his armies' distress and ordered a retreat. During the night, the Confederates withdrew, greatly disorganized, to their fortified stronghold at Corinth. Possession of the grisly battlefield passed to the victorious Federal's, who were satisfied to simply recapture Grant's camps and make an exhausted bivouac among the dead.
General Johnston's massive and rapid concentration at Corinth, and surprise attack on Grant at Pittsburg Landing, had presented the Confederacy with an opportunity to reverse the course of the war. The aftermath, however, left the attacking Union forces still poised to carry out the capture of the Corinth rail junction. Shiloh's awesome toll of 23,746 men killed, wounded, or missing brought a shocking realization to both sides that the war would not end quickly.