1861-1877: Library of Congress
In 1861, the United States faced its greatest crisis to that time. The northern and southern states had become less and less alike - socially, economically, politically. The North had become increasingly industrial and commercial while the South had remained largely agricultural. More important than these differences, however, was African-American slavery. Northerners generally wanted to limit the spread of slavery; some wanted to abolish it altogether. Southerners generally wanted to maintain and even expand the institution. Thus, slavery became the focal point of a political crisis.
See the American Civil War, from Wikipedia:
The American Civil War (April 12, 1861 – May 26, 1865; also known by other names) was a civil war in the United States between the Union ("the North") and the Confederacy ("the South"), which was formed in 1861 by states that had seceded from the Union. The central conflict leading to war was a dispute over whether slavery should be permitted to expand into the western territories, leading to more slave states, or be prohibited from doing so, which many believed would place slavery on a course of ultimate extinction.
See the Reconstruction Era, from Wikipedia:
The Reconstruction era was a period in United States history and Southern United States history that followed the American Civil War and was dominated by the legal, social, and political challenges of the abolition of slavery and the reintegration of the eleven former Confederate States of America into the United States. During this period, three amendments were added to the United States Constitution to grant citizenship and equal civil rights to the newly freed slaves. To circumvent these legal achievements, the former Confederate states imposed poll taxes and literacy tests and engaged in terrorism to intimidate and control people of color and to discourage or prevent them from voting.
See the Jim Crow Era, from Wikipedia:
The Jim Crow laws were state and local laws introduced in the Southern United States in the late 19th and early 20th centuries that enforced racial segregation, "Jim Crow" being a pejorative term for an African American.The last of the Jim Crow laws were overturned in 1965. Formal and informal racial segregation policies were present in other areas of the United States as well, even as several states outside the South had banned discrimination in public accommodations and voting. Southern laws were enacted by white-dominated state legislatures (Redeemers) to disenfranchise and remove political and economic gains made by African Americans during the Reconstruction era. Such continuing racial segregation was also supported by the successful Lily-white movement.