By the 1850s, slavery had split America in two. In the North, many worked to end slavery.
Northerners joined antislavery groups. They gave out leaflets on the streets. They also held fairs and concerts to raise money to help slaves escape. The Underground Railroad made Southerners angry. They were also angry with Northerners who disobeyed the Fugitive Slave Laws. By 1860, many Southerners felt that the only way to protect slavery was to secede from (leave) the Union. They also wanted to protect the rights of Southern states. So they planned to form a separate country. President Abraham Lincoln said that was against the law. He sent the Union Army to stop them. This led to a bloody fight between the North and South. The Civil War started in 1861 and lasted four years. When the Union Army finally won, African Americans all over the United States were free at last.