The American Civil War (1861–1865) was a civil war in the United States of America. It was fought when 11 Southern states left the United States and formed the Confederate States of America (also called the Confederacy). The US government and the states that remained loyal to it were called the Union.

The main cause of the war was slavery, which was allowed in the South, including all 11 Confederate States. Slavery was illegal in most of the North. The Confederate States tried to leave the Union after Abraham Lincoln, who disliked slavery, was elected US president. The Union believed that it was illegal for the states to break away. There were five states that allowed slavery which stayed in the Union.

The war began on April 12, 1861, when Confederate forces attacked Fort Sumter, a fort in South Carolina that was held by Union soldiers. The war lasted four years and caused much damage in the South. Most battles were in northern states until 1862 and in southern states after 1862.

After four years of fighting, the Union won the war, and soon, slavery was made illegal everywhere in the United States of America.

Background 
When the United States of America was founded in 1776, most states allowed slavery. However, over the next 84 years, the Northern states decided that slavery was a bad thing and banned it. The Southern states kept slavery legal. Slaves from Africa grew tobacco, cotton and other cash crops in those states. It was very different in the North, where the Industrial Revolution led to more people working in factories instead of on farms.

The United States became divided into slave and free states. By 1860, those groups were angry at each other. Few people wanted to end slavery in the South and so Americans argued on whether slavery should be allowed to spread to the territories and new states in the west. In the late 1850s, there was fighting in Kansas over whether the territory should allow slavery.

Abraham Lincoln from the Republican Party won the 1860 United States presidential election. He then did not want to ban slavery in the states. Like nearly everyone else, he believed that the US Constitution did not allow the federal government to ban slavery (the amendment to ban slavery was passed later, in 1865). He also thought that banning it suddenly would anger the South.

Instead, Lincoln and his Republican Party thought that slavery should be banned in US territories. They thought that slavery would die out if it could not go to new places.

Lincoln became president on March 4, 1861. In the four months between the election and the day that Lincoln became president, seven Southern states declared their independence from the Union. The outgoing US president, James Buchanan, said that was against the law but he could do nothing to stop them.

The Republican Party treated secession as a rebellion. No country in the world ever recognized the Confederacy as a separate nation. That was because of diplomacy on the part of the Union, anti-slavery feelings in Europe and the northern blockade of southern ports, and of war against the United States.

The first seven states to join the Confederacy were South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, and Texas. Four others joined after the fighting began: Virginia, Arkansas, Tennessee, and North Carolina. The Confederacy claimed Kentucky and Missouri belonged to them, but they never joined the Confederacy. Kentucky, Missouri, and Maryland were slave states that tried to avoid taking sides. Delaware supported the Union although it was a slave state. Also, the western counties of Virginia chose to remain in the Union and created a new state, West Virginia.

Fighting begins 
Fighting started when the Confederates shot and threw bombs at Fort Sumter, a Union Army fort in South Carolina. Lincoln then asked the Union states to bring soldiers to fight the Confederates.

The Confederates said that all forts and other federal buildings in the South belonged to them. Fort On April 12, 1861, Confederate forces attacked the fort and forced the Union soldiers in it to surrender. Lincoln then asked every Union state for volunteers to join the Union Army. Four more southern slave states joined the Confederates, rather than supply forces to fight against them.

The US Navy stopped other ships from going in or out of southern ports. That stopped the Confederacy from selling its cotton and other goods and also made it harder for the South to buy weapons and military supplies.

The war

The American Civil War was fought in three important land areas, or "theaters." The Eastern Theater was the land east of the Appalachian Mountains. The Western Theater included everything between the Appalachian Mountains and the Mississippi River and along the river. The Trans-Mississippi Theater included territory west of the Mississippi River.

Both the United States and the Confederacy had their capital cities in the Eastern Theater. Washington, DC, had been the US capital since 1800. When the South seceded, its first capital was Montgomery, Alabama, but it moved the capital to Richmond, Virginia. Both cities are only about 90 miles (145 km) apart.

One of the first battles of the war was fought in Virginia. The First Battle of Bull Run, on July 21, 1861, was a Confederate victory. The Union Army of the Potomac then tried to capture Richmond in the Peninsula Campaign during the spring of 1862, but Robert E. Lee became leader of the Army of Northern Virginia and defeated the Union Army. He then won the Second Battle of Bull Run in August 1862. Lee tried to win the war by invading Maryland, but he lost the Battle of Antietam and retreated to Virginia.

There was much fighting between ships in the war, but the Union had a stronger and bigger navy. Lincoln put the Confederates under a blockade and so the Union Navy would not let any ships into or out of southern ports. The Confederates used ships called blockade runners to bring things from Europe like weapons. The navies of each side also fought on the rivers. The ships included ironclads, which were protected by iron on their sides, and cottonclads, which used cotton along their sides. During the Battle of Hampton Roads, the Confederate ironclad Virginia fought against the Union ironclad Monitor. It was the first time in world history that two ironclads fought each other.

In the Western Theater, much of the fighting happened along the Mississippi River. Ulysses S. Grant was an important Union general in the West. The Confederates tried to send their soldiers into the state of Kentucky in the summer of 1861. In the early months of 1862, the Union Army made the Confederates retreat from Kentucky and from western Tennessee. They tried to recapture western Tennessee by attacking Grant's army at the Battle of Shiloh, but Grant won the battle. The Confederates then tried to send their soldiers into eastern Kentucky in the fall of 1862 but lost the Battle of Perryville and then left Kentucky.

The North won control of almost all of the Mississippi River by capturing the cities along the river in the fall of 1862 and the spring of 1863. However, the Confederacy still held Vicksburg, an important city and fort. If they held, the Confederates could move soldiers and supplies from one side of the river to the other. Grant started the Siege of Vicksburg during the month of May 1863. The siege continued until July 4, 1863, when the Confederates there surrendered to Grant. That was one of the turning points in the war by dividing the Confederacy into two parts.

There were also battles west of the Mississippi River Valley in the Trans-Mississippi Theater. For example, two important battles were the Battle of Wilson's Creek and the Battle of Pea Ridge. The Confederates tried to invade New Mexico in February and March 1862 but they were defeated at the Battle of Glorieta Pass. After the Union captured Vicksburg, the area became separated from the rest of the Confederate States. Other battles happened in the area after the capture of Vicksburg.

During the Siege of Vicksburg in the west, another turning point came in the east. After winning some battles, Lee decided to invade the North again. Lee and his Army of Northern Virginia went into Pennsylvania. The Confederate Army met the Union Army near Gettysburg, Pennsylvania and fought the Battle of Gettysburg, which lasted from July 1 to 3, 1863. More soldiers died at Gettysburg than in any other Civil War battle, which the Union won. Lee and his troops were pushed back into the South and could no longer invade the North.

Lincoln then decided that Grant was his best general and put Grant in control of all Union armies. Lincoln also made William Tecumseh Sherman the general in charge of the Union troops in Georgia. Grant led many attacks on Lee's army. The battles were made up the Overland Campaign.

Meanwhile, Sherman burned Atlanta and Savannah to try to weaken the South and to make it harder to supply the Confederate Army. He then marched north through South Carolina and North Carolina. Confederate General Joseph E. Johnston attacked Sherman at the Battle of Bentonville. Sherman won the battle. Even in the 20th century, Southerners remember Sherman's march as destroying many homes, farms, and railroads, but his soldiers are blamed for things that they could not have done since they were too far away.

Eventually, Lee decided that he had too few soldiers to keep on fighting the Union, which had more soldiers and supplies. He surrendered to Grant on April 9, 1865 near Appomattox Court House. Later, many other Confederate armies surrendered as well. The last Confederate general to surrender was Brigadier General Stand Watie, who surrendered on June 23, 1865, in Oklahoma.

After the war ended, Lincoln pardoned all of the Confederate soldiers and so they could not be arrested or punished for fighting against the Union. The South would be allowed to rejoin the United States but only later. Some Confederates did not want to return to the United States and moved to places like México or Brazil.

Why the Union won
Historians have had different ideas about whether the Confederacy could have won the war. Most of them, such as James McPherson, say that it would have been difficult but possible. The Union had far more people, money and industry. By most estimates, the Union had over 2 million soldiers while the Confederacy had 1 million.

One advantage the Confederacy had was that they only needed to defend their land, whereas the Union could only win if they took full control the Confederate states. Furthermore, the Union could only fight the war if their people wanted them to keep fighting. Lincoln had opponents in the North (the Copperheads) who wanted the war to end. If the Confederacy had defended itself for long enough, it may have led to more people in the Union turning against the war and supporting the Copperheads. However, Lincoln held on to his support and won the 1864 election. 

The Union Navy blocked ships from going into the Confederate ports. Although some ships managed to get past, most could not. The Confederacy had big money problems because they could not sell cotton and other goods to other countries. The Confederacy collected less taxes than the Union, so they printed money to pay for the war. This caused inflation (rising prices).

Another factor was that the Confederacy could not get help from outside. They had hoped that Britain and France would support the Confederacy because they wanted to buy their cotton. However, Britain and France did not give them help. There were three reasons for this. Firstly, they thought that slavery was wrong. Secondly, they did not want to become enemies of the United States. Thirdly, they could get cotton from elsewhere.

Most historians also think that Abraham Lincoln was a better leader than Jefferson Davis. Don E. Fehrenbacher says that Lincoln's skills helped keep the Border States and ordinary people on his side. Lincoln left his generals alone if they did a good job and fired them if they did not. Davis lacked a clear plan, tried to do too many tasks at once and often chose people to do jobs just because they were his friends. He annoyed his generals and other Confederate politicians. William Cooper says that better leadership helped the Union, but they were already more likely to win.

After the war
Many soldiers on both sides died during the war. Most of the war was fought in the South. Many railroads, farms, houses and other things were destroyed, and most people there became very poor.

The period after the war, called Reconstruction, lasted from the end of the war to 1877. The Union Army stayed in some Southern states and made them occupied territory. Three important amendments were added on to the US Constitution. The amendments were proposed (or suggested) by the US government. Although not every American supported them, they got enough support to pass:
 The Thirteenth Amendment says that slavery is not allowed anywhere in the United States, which completed the work of the Emancipation Proclamation.
 The Fourteenth Amendment makes it clear that all people born in the United States are citizens, and all citizens have equal rights.
 The Fifteenth Amendment says that people in the United States could not be kept from voting because of their race.

After the war, some of the Union Army's leaders went into politics. Generals Grant, Hayes, Garfield, Harrison, and McKinley became US presidents. Other veterans were elected to other offices.

The Southern states were allowed to ask to rejoin the union. When they were accepted, that could send senators and representatives to the US Congress again and make their own state laws. During Reconstruction, black Americans built schools and other social infrastructure. Some of the schools became the historically-black colleges that still exist. After southern states rejoined the Union, most of them made laws that limited what black people could do.

The Amnesty Act of 1872 restored the rights to vote and to hold political office for most former members of the Confederacy. Some of them also became politicians.

References

Other sources
 Gibboney, Douglas Lee. Tragic Glory: A Concise, Illustrated History of the Civil War. Fredericksburg, Virginia: Sergeant Kirkland's, 1997. .
 Roland, Charles P. An American Iliad: The Story of the Civil War. New York: McGraw-Hill, 2002. .

Other websites

 Civilwar.com
 American Civil War Citizendium

 
Wars involving the United States
Rebellions in North America
19th century rebellions