What Was Deadliest War in American History?

The deadliest war in American history is undoubtedly the American Civil War. This devastating conflict, which lasted from 1861 to 1865, claimed the lives of more than 620,000 soldiers and civilians.

The war was fought between the Union states of the North and the Confederate states of the South. The primary cause of the war was slavery, which had become a major issue in the years leading up to the conflict.

The Causes

The issue of slavery had been a contentious one since before America’s founding. By the mid-19th century, tensions between Northern and Southern states had reached a boiling point.

The South relied heavily on agriculture and slave labor to maintain their way of life. In contrast, the North was rapidly industrializing and did not require slaves for their economy.

The Election of Abraham Lincoln

In November 1860, Abraham Lincoln was elected as President of the United States. His victory was seen by many Southerners as a direct threat to their way of life, as Lincoln opposed slavery and supported its eventual abolition.


In response to Lincoln’s election, several Southern states began to secede from the Union and form their own government. By February 1861, seven states had seceded and formed the Confederate States of America.

The War

The Civil War began on April 12, 1861 when Confederate forces attacked Fort Sumter in South Carolina. The conflict quickly escalated into a full-scale war that involved most of America’s states.

Major Battles

Some of the major battles fought during the war include:

  • The Battle of Gettysburg (July 1-3, 1863)
  • The Battle of Antietam (September 17, 1862)
  • The Battle of Shiloh (April 6-7, 1862)
  • The Battle of Vicksburg (May 18-July 4, 1863)

The Aftermath

The Civil War ended on April 9, 1865 when Confederate General Robert E. Lee surrendered to Union General Ulysses S. Grant at Appomattox Court House in Virginia.

Death Toll

The war had a devastating impact on the United States. Over the course of four years, more than 620,000 soldiers and civilians were killed. This is more than the total number of Americans killed in all other wars combined.


After the war, the country faced the daunting task of rebuilding and healing from the conflict. The period following the war, known as Reconstruction, was marked by political and social upheaval as the country struggled to come to terms with its past and move forward.

In conclusion, the American Civil War was by far the deadliest conflict in American history. Its impact on the country was profound and lasting. The war remains a stark reminder of America’s past and serves as a cautionary tale about how deep-seated divisions can lead to devastating consequences.