The Battle of Shiloh was a significant early battle in the American Civil War, fought from April 6 to April 7, 1862, in Tennessee. It involved the Union Army, led by General Ulysses S. Grant, and the Confederate Army, commanded by General Albert Sidney Johnston. The battle began with a surprise attack by the Confederates, catching the Union forces off guard. Over two days, fierce fighting resulted in heavy casualties on both sides, with around 23,000 soldiers killed or wounded. Ultimately, the Union emerged victorious, which helped secure their control over the Tennessee River and marked a turning point in the war.